Data Sufficiency

Marry, Dora, Christie, and Lucy took a math test of total 50 marks. Christie scored 4 marks less than Marry scored and Dora scored 10 marks more than Lucy scored. If the average (arithmetic mean) of their scored marks is same as what Dora scored in the test, how many marks did Christie score in the test?
(1) Marry and Dora together scored 83 marks in the test.
(2) Christie and Lucy together scored 69 marks in the test.


Made Up!

Marry, Dora, Christie, and Lucy took a math test of total 50 marks. Christie scored 4 marks less than Marry scored and Dora scored 10 marks more than Lucy scored. If the average (arithmetic mean) of their scored marks is same as what Dora scored in the test, how many marks did Christie score in the test?
(1) Marry and Dora together scored 83 marks in the test.
(2) Christie and Lucy together scored 69 marks in the test.

Christie =C
Marry = M
Dora = D
Lucy = L

Now, C = M-4 ==> M = C+4
D = L+10 ==> L = D-10
(C+M+L+D)/4 = D ==> C+M+L = 3D ==> C+(C+4)+(D-10) = 3D ==> 2C-6 = 2D ==> D=C-3
C=?

Statement 1) M+D = 83 ==>(C+4) +D = 83 ==>(C+4)+(C-3)=83 ==> C=41 Sufficient
Sufficient

Statement 2) C+L = 69 ==> C+(D-10)=69 ==> C+(C-3)-10 = 69 ==> C=41 Sufficient

Answer: Option-D

Hi
Got the answer as D

but took more time for solving this simple question

thanks and regards

unknown13 wrote:Hi
Got the answer as D

but took more time for solving this simple question

thanks and regards

In a DS problem, we don't really need to finish the calculation. The moment we feel a unique answer may or may not be reached, we should STOP, take DECISION, and save the precious TIME.