Page 23 - SM inner class 7.cdr

4 Ex am ple 25. Maddy read three-fifth of 75
´ Number = 84
7 pages of his les son. How many more pages he
4 need to com plete the les son?
Number = 84 ¸
7 So lu tion : Maddy read = 3 of 75
7 5
Number = 84 ´
4 = 3 ´75
[Here we need to multiply 84 by the reciprocal 5
4 = 45 pages.
of ]
7 Maddy has to read = 75 – 45 = 30

= 21 7 = 30 pages more
´
= 147 Therefore, Maddy has to read 30 more pages.
Therefore, the number is 147. Ex am ple 26. A herd of cows gives 4 litres of
Ex am ple 24. One half of the students in a milk each day. But each cow gives one-third of
3 to tal milk each day. They give 24 litres milk in
school are girls, of these girls are study ing in
5 six days. How many cows are there in the herd?
lower classes. What fraction of girls are So lu tion : A herd of cows gives 4 litres of milk
study ing in lower classes? each day. Each cow gives one-third of to tal milk
1 1
So lu tion : Frac tion of girls study ing in school = each day = of 4
2 3
3 1 4
Fraction of girls studying in lower classes = of Therefore, each cow gives of milk each day.
5 2 3
3 1 4
= ´ Total no. of cows = 4 ¸
5 2 3
3 3
= = 4 ´
10 4
3 = 3
Therefore, of girls studying in lower classes.
10 Therefore there are 3 cows in the herd.

E xercise 2.4

1. How many one-fifths are there in 500?
2. The prod uct of 9/7 and a num ber is 126. Find the num ber.
3. Six-ninths of a num ber is 36. Find the num ber.
4. 2/5 of a class of 45 are boys. Find the num ber of girls in the class.
5. Rohan drank or ange juice from a 500 ml bot tle. He found that 3/5 was re main ing. How much did he drink?

6. Raunak and two of his friends ate one-fourth each of an eight slice pizza. Find the re main ing slice of the pizza.
7. Out of a class of 150, one-third opted for Cricket, two-fifth for Ten nis and rest for Bad min ton. Find how
many opted for Bad min ton?
8. Fifty di vided by half mi nus forty. What is the an swer?
9. Ninety five di vided by one- fifth plus thirty five. What is the an swer?

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Mathematics In Focus - 7