In a school the ratio of boys and girls is 4 : 5 respectively. When 100 girls leave the school the ratio becomes 6 : 7 respectively. How many boys are there in the school ?
A. 1300
B. 1500
C. 1600
D. Cannot be determined
E. None of these
Answer: Option E
Solution(By Examveda Team)
Let the number of boys and girls be 4x and 5x respectively.Then,
$$\eqalign{ & {\text{ = }}\frac{{4x}}{{5x - 100}} = \frac{6}{7} \cr & \Rightarrow 28x = 30x - 600 \cr & \Rightarrow 2x = 600 \cr & \Rightarrow x = 300 \cr & \therefore {\text{Number of boys}} \cr & = 4 \times 300 \cr & = 1200 \cr} $$
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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