TEST35 #16

[dunkin77]

A breakfast that consists of 1 ounce of corn puffs and 8 ounces of fruit X provides 257 calories. When 8 ounces of fruit Y is substituted for the 8 ounces of fruit X, the total number of calories is reduced to 185. If fruit X provides 1.8 times as many calories as fruit Y, how many calories does 8 ounces of fruit Y alone provide ?
(A) 11.25
(B) 72
(C) 90
(D) 95
(E) 129.6


Hi,

My answer was A) but it says the correct answer is C) --- Can anyone explain?

[Prasanna]

We get two equations

a+8x=257
a+8y=185

From this we get 8x-8y=72 which is x-y=9

We also know x=1.8y. Substituting this in x-y=9 we get

.8y=9 or y=90/8

For 1 ounce the calories obtained from y in 90/8. From 8 ounces we get 90 calories. Hence C.

[Cybermusings]

1c + 8x = 257 ----- 1)
1c + 8y = 185 ------- 2)
x = 1.8 y ------ 3)
Now substitute y for x in equation 1)
c + 8 (1.8y) = 257
c + 14.4y = 257 ---- 1)
c + 8y = 185

6.4y = 72
y = 72/6.4
8y = 72/6.4 * 8 = 90 calories

[ns88]

X- Y= 257-185=72

X-Y= 72

X=1.8Y

1.8Y-Y=72

Y=90