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Out of two sections A and B, 10 students of section B shift to A, as a result strength of A becomes 3 times the strength of B. But , if 10 students shift over from A to B, both A and B become equal in strength. Ratio of the number of students in section A that of section B is ?
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- 2 : 1
- 5 : 3
- 3 : 1
- 9 : 4
Correct Option: A
A +10 = 3(B - 10)
⇒ A - 3B = -20 ....(i)
And ( A - 10) = (B + 10)
⇒ A - B = 20 ...(ii)
on subtracting Eq.(ii) from Eq.(i), we get
(A - 3B) - (A - B) = -20 - 20
⇒ - 2B = - 40
there4; B = 20
Now, by using Eq. ...(ii),
there4; Ratio of the numbers of students of A and B = 40 : 20 = 2 : 1
