Multiplying fractions by whole numbers :
To multiply a proper or improper fraction with the whole number,first, we have to multiply the whole number with the numerator of the fraction, keeping the denominator same.
2 x 3/5 = 6/5
3 x 7/11 = 21/11
To multiply a mixed fraction by a whole number, first convert the mixed fraction to an improper fraction and then multiply.
4 x 3 4/7 = 4 x 25/7 = 100/7 = 14 2/7
Example 1 :
Find 4 x 1/7
4 x 1/7 = 4/7
Example 2 :
Find : 1/4 of 2 1/5
1/4 of 2 1/5 = 1/4 x 2 1/5
1/4 of 2 1/5 = 1/4 x 11/5
1/4 of 2 1/5 = 11/20
Example 3 :
In a group of 60 students 3/10 of the total number of students like to study Science, 3/5 of the total number like to study Math.
(i) How many students like to study Science ?
(ii) How many students like to study Math ?
(i) Out of 60 students, 3/10 of the students like to study Math.
Thus, the number of students who like to study Science is
= 3/10 of 60
= 3/10 x 60
(ii) Out of 60 students, 3/5 of the students like to study Math.
Thus, the number of students who like to study Math is
= 3/5 of 60
= 3/5 x 60
= 3 x 12
Example 4 :
A car runs 20 miles using 1 liter of petrol. How much distance will it cover using 2 3/4 liters of petrol ?
No. of miles covered in 1 liter of petrol = 20
Thus, no. of miles covered in 2 3/4 liters of petrol is
= 2 3/4 of 20 miles
= 2 3/4 x 20 miles
= 11/4 x 20 miles
= 55 miles
After having gone through the stuff given above, we hope that the students would have understood "Multiplying fractions by whole numbers".
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