When 5 children from class A join class B, the number of children in both classes is the same. If 25 children from B, join A, then the number of children in A becomes double the number of children in B. The ratio of the number of children in A to those in B is:
A. 19 : 18
B. 9 : 8
C. 18 : 17
D. 19 : 17
Answer: Option D
Solution(By Examveda Team)
\[\begin{array}{*{20}{c}} {}&{{\text{A}}\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{B}}\,} \\ {{\text{Student}}}&{x - 5 = y + 5} \end{array}\]$$\eqalign{ & x - y = 10\,.\,.\,.\,.\left( {\text{i}} \right) \cr & x + 25 = 2\left( {y - 25} \right) \cr & x - 2y = - 75\,.\,.\,.\,.\left( {{\text{ii}}} \right) \cr & {\text{Subtract both equation}} \cr & x - y = 10 \cr & x - 2y = - 75 \cr & \underline {\, - \,\,\, + \,\,\,\,\,\,\, + \,\,\,\,\,} \cr & \,\,\,\,\,\,\,\,\,\,y = 85 \cr & x = 95 \cr & x:y = 95:85 = 19:17 \cr} $$
Related Questions on Ratio
If a : b : c = 3 : 4 : 7, then the ratio (a + b + c) : c is equal to
A. 2 : 1
B. 14 : 3
C. 7 : 2
D. 1 : 2
If $$\frac{2}{3}$$ of A=75% of B = 0.6 of C, then A : B : C is
A. 2 : 3 : 3
B. 3 : 4 : 5
C. 4 : 5 : 6
D. 9 : 8 : 10
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