For the following questions answer them individually
In a family, the father's age is 5 times the age of one of his sons. Mother's age is 4 times the age of their other
son. Difference in the parents' ages is half the sum of the sons' ages. Then:
A man stands 10 m in front of a large plane mirror. How far must he walk before he is 5 m away from his image?
The ratio of the number of boys and girls in a school is 3 : 2. If 20% of the boys and 25% of the girls are scholarship holders, what percentage of the students do NOT get scholarship?
When a positive number is decreased by 4, it is equal to 21 times the reciprocal of the number. Find the number.