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SSC CHSL 2022 PYQ — Question 69

SSC CHSL - 30 May 2022 - Shift 2 • Quantitative Aptitude • Q69

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A is the average mark of a group of 10 students in a class and A + 8 is the average of a group of 15 students which includes the group of 10 students as given. The total marks obtained by the group of 10 students is X and the total marks obtained by the group of 15 students is Y. If X : Y = 3 : 5, then the value of A + X + Y is _________.

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Correct answer: D

Explanation

The correct answer is Option 4 i.e. 1992.

We know that,

Sum of marks = Average marks × Number of students

Now,

X = 10A   ....(i)

and, Y = 15(A + 8)   ....(ii)

Now dividing equation (i) by equation (ii), we get

XY=10A15(A+8)=35{X \over Y} = {10A \over 15(A + 8)} = {3 \over 5}

⇒ 10A15(A+8)=35{10A \over 15(A+ 8)} = {3 \over 5}

⇒ 50A = 45A + 360

⇒ 5A = 360

⇒ A = 72

Putting A = 72 in both equations (i) and (ii), we get

⇒ X = 720

⇒ Y = 1200

Now,

A + X + Y = 72 + 720 + 1200 = 1992

Hence, the required answer is 1992