Page 40 - Math_Genius_V1.0_C7_Flipbook

D:\Surender Prajapati\CBSE_ICSE_Book_New\CBSE\Grade-7\Math_Genius-7\Open_File\02_Chapter\02_Chapter
\ 15-Nov-2024 Surender Prajapati Proof-6 Reader’s Sign _______________________ Date __________

7. A water tank can hold 1000 litres of water. Due to an electricity breakdown, the tank could fill only
3 of its capacity. How many liters of water are filled in the tank?
5

8. A fruit seller has 250 kg of apples in a cold store, but 4 have been rotten. How many apples are
15
rotten? Also, find the quantity of apples in the cold store that are in good condition.

4 12
9. Provide the number in the box , such that × = . Out of all three fractions, which one
is greater. 5 35

Multiplicative Inverse of a Fraction (Reciprocal)

We know that two numbers are said to be reciprocal of each other if their product is 1. Similarly,
two fractions are reciprocal of each other if their product is 1.
4 7
For example: The reciprocal of is .
7 4
×
4 7 47
i.e., × = = 1 .
7 4 74 FACTS
×
• The reciprocal of a proper
a fraction is an improper fraction.
In general, multiplicative inverse (reciprocal) of a fraction is
b b a b • The reciprocal of an improper
a and of is if the product of both fractions is 1. fraction is a proper fraction.
b
a
a b • The reciprocal of a whole
i.e., × =1 number (except 0) will always
b a a unit fraction.
Thus, we can say, if numerator and denominator of a fraction are interchanged, then the
fraction formed is called the reciprocal of the given fraction.

Example 8: Find the reciprocal of the following fractions:
2 7 3 4 3
(a) (b) (c) 1 (d) ×
3 5 4 9 8

2 3 2 3
Solution: (a) Reciprocal of is . As × = 1
3 2 3 2
7 5 7 5
(b) Reciprocal of is . As × = 1
5 7 5 7
3 7
(c) Since, 1 =
4 4
3  7 4 7 4
Therefore, the reciprocal of 1  =  is . As, × = 1
4  4  7 4 7
4 3 43 12 1
×
(d) Since, × = = =
9 8 98 72 6
×
4 3  1 1 6
Therefore, the reciprocal of ×  =  is 6. As, × = 1
9 8  6  6 1

Mathematics-7 38