Question 32
Back to Exercise
In a class there are certain no. of boys and girls. If 15 girls are absent then no. of boys will be twice that of girls. If 45 boys are absent then girls strength will be 5 times that of boys. Find number of boys actually present ?
- A 40
- B 50 Correct
- C 55
- D 35
Correct Answer: Option B
15 girls are absent => b = 2(g-15)...... eqn...(1)
45 boys are absent => g - 15 = 5(b-45).....eqn...(2)
=> g = 5(b-45) + 15
=> b = 2((5(b-45)+15)-15)
=> b = 2(5b - 225 + 15 - 15)
=> b = 2(5b-225)
=> b = 10b - 450
=> 9b = 450
=> b = 50
so from equation(2)
g - 15 = 5(b - 45)
=> g - 15 = 5(50-45)
=> g - 15 = 5(5)
=> g = 25 + 15
=> g = 40
Therefore, the number of boys = 50 and girls = 40
Discussion & Comments 0
Share your method, a shortcut, or ask about a step you didn't follow.
No comments yet. Be the first to share your solution!