जॉइन Examsbookउत्तर : 2. "50"
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 ?5
प्र: 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 ?
- 140false
- 250true
- 355false
- 435false
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उत्तर : 2. "50"
व्याख्या :
Answer: B) 50 Explanation: 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