Problem Solving

As advertised on the main page of Beat the GMAT, Ashley, Brian, and I will be posting some original questions today and tomorrow with prizes for the first five students to respond with correct answers that show your work!

Good Luck!

The Ratio of the number of children to adult women at the picnic is 20 : 7. The ratio of children to adult men at the same picnic is 15 : 3. If the organizers are able to double the ratio of adult men to children, what is the new ratio of children to adults at the picnic?

A) 6 : 5

B) 4 : 3

C) 30 : 21

D) 15 : 6

E) 8 : 3

Tell me that is true..
Pleaseeeeeeeeeeeeeeeee
The ratio originally :
Children: Adult Women = 20 : 7

Children: Adult Male = 15 : 3

Combined Ratios :
Children : Adult Women : Adult Male= 60 : 21 :12

Now Ratio of Children: Adult Male is doubled
So, Children: Adult Male = 60 : 24

Therefore, the new Ratio is :
Children : Adult Women : Adult Male= 60 : 21 : 24

Therefore , The Ratio of Children : Adults = 60 :45 or 4 : 3

Therefore, B.

Answer is C 4:3

Children:Women = 20:7 --> 60:21
Children:Men = 15:3
New ratio of Children:Men = 15:6 --> 60:24

Ratio of Children:Adult = 60:(21+24) = 60:45 = 4:3

Sorry B - 4:3

For 7 women - 20 children
For 3 men -15 children
-> for 4 men - 20 children

Combined ration of
Adult women : Adult men : children - 7x:4x:20x

Doubling adult men to children ratio - 7x:8x:20x

So, new ratio of children to adult - 20x/(8x+7x)

-> 20/15 ->4/3

Ans : B) 4: 3

Answer : B

Lets assume the number of children: 100

From the prompt,Since the ration of children to adult women is 20:7,the number of adult women = 35, and the ratio of number of children to adult men is 15:3, the number of men = 20.

From the prompt, if the ratio of number of adult men to children are doubled, the ratio will be 6:15, and consequently the number of adult men will change from 20 to 40.

New information:

The Number of children : 100
The number of adult women: 35
The new number of adult men: 40
Total number of adults: 75

The ratio of number of children to number of adult = 100/75 = 4:3

Answer : B

Only 4 people have answered so far...anyone else?

Answer B.

C:W = 20:7
C:M = 15:3

If M:C doubled, new C:M = 15:6

Combined Ratio W:C:M = 21:60:24

Ratio of Children:Adults = 60:(21+24) = 60:45 = 4:3

The ratio given originally :
Children: Adult Women = 20 : 7
Children: Adult Male = 15 : 3

Combining the Ratios we get :
Children : Adult Women : Adult Male= 60 : 21 :12

Now Ratio of Children: Adult Male is doubled
So, Children: Adult Male = 60 : 24

Therefore, the new Ratio is :
Children : Adult Women : Adult Male= 60 : 21 : 24

Therefore , The Ratio of Children : Adults = 60 :45 or 4 : 3
where Adults = Adult women + Adult Men

Hence Answer is B

David@VeritasPrep wrote:As advertised on the main page of Beat the GMAT, Ashley, Brian, and I will be posting some original questions today and tomorrow with prizes for the first five students to respond with correct answers that show your work!

Good Luck!

The Ratio of the number of children to adult women at the picnic is 20 : 7. The ratio of children to adult men at the same picnic is 15 : 3. If the organizers are able to double the ratio of adult men to children, what is the new ratio of children to adults at the picnic?

A) 6 : 5

B) 4 : 3

C) 30 : 21

D) 15 : 6

E) 8 : 3

C:W 20:7 C:M 15:3 double M:C 6:15

C:W:M
300 : 105: 120

300/105+120 = 300/225 = 12/9 = 4/3

number of children = lcm of 15,20 = 60

thus c=60,w=21 and m=12
new ratio c=60,w=21 and m=24

thus c/(w+m) = 60/45=4/3

David@VeritasPrep wrote:As advertised on the main page of Beat the GMAT, Ashley, Brian, and I will be posting some original questions today and tomorrow with prizes for the first five students to respond with correct answers that show your work!

Good Luck!

The Ratio of the number of children to adult women at the picnic is 20 : 7. The ratio of children to adult men at the same picnic is 15 : 3. If the organizers are able to double the ratio of adult men to children, what is the new ratio of children to adults at the picnic?

A) 6 : 5

B) 4 : 3

C) 30 : 21

D) 15 : 6

E) 8 : 3

The answer is B.

What we know :
C/W = 20/7
C/M = 15/3 -> but then M/C is doubled -> M/C = 2 x (3/15) = 6/15

What's being asked :
C/(M+W)

Answer :
M = (6/15) x C
W = (7/20) x C
M+W = 6C/15 + 7C/20 = 45C/60
C/(M+W) = C/(45C/60) = 60/45 = 4/3 (B)

Answer is B:

Initial Ratio:

Children 20 : Female Adults 7
Children 15 : Male Adults 3

Double M.A. -- ratio becomes C 15 : MA 6

Now we combine the data -- find a common multiple for Children: 60

This triples the C:FA ratio, and quadruples the C:MA ratio, creating:

C60:FA21:MA24

Combine the adults:
C60:A45 -- ratio becomes 4:3, thus answer is B.

David@VeritasPrep wrote:As advertised on the main page of Beat the GMAT, Ashley, Brian, and I will be posting some original questions today and tomorrow with prizes for the first five students to respond with correct answers that show your work!

Good Luck!

The Ratio of the number of children to adult women at the picnic is 20 : 7. The ratio of children to adult men at the same picnic is 15 : 3. If the organizers are able to double the ratio of adult men to children, what is the new ratio of children to adults at the picnic?

A) 6 : 5

B) 4 : 3

C) 30 : 21

D) 15 : 6

E) 8 : 3

My Answer: B