Page 229 - Start Up Mathematics_6

(b) Ratio of number of squares to the circles inside the rectangle = 2 : 3

(c) Ratio of number of circles to all the figures inside the rectangle = 3 : 9 = 1 : 3
Example 4: The distance travelled by Roy and Akhtar in an hour is 8 km and 6 km. Find the
ratio of speed of Roy to the speed of Akhtar.
Solution: Speed of Roy = 8 km/h

Speed of Akhtar = 6 km/h
Ratio of speed of Roy to speed of Akhtar 8 : 6 = 4 : 3

Example 5: Find the ratio of the following:
(a) 33 km to 66 km (b) 40 minutes to 1.5 hours (c) 40 cm to 1.5 m
(d) 75 paise to ` 1 (e) 400 mL to 2 L

Solution: (a) 33 km to 66 km = 33 : 66 = 1 : 2
(b) 40 minutes to 1.5 hours = 40 minutes to 90 minutes = 40 : 90 = 4 : 9
(c) 40 cm to 1.5 m = 40 cm to 150 cm = 40 : 150 = 4 : 15

(d) 75 paise to ` 1 = 75 paise to 100 paise = 75 : 100 = 3 : 4
(e) 400 mL to 2 L = 400 mL to 2000 mL = 400 : 2000 = 1 : 5

Example 6: In a year, Reema earns ` 2,50,000 and saves ` 50,000. Find the ratio of:
(a) money that Reema saves to the money she earns in a year.
(b) money that she saves to the money she spends in a year.
Solution: Money Reema earns = ` 2,50,000
Money Reema saves = ` 50,000
Money Reema spends = ` 2,00,000
(a) Money that Reema saves to the money she earns = 50,000 : 2,50,000 = 1 : 5

(b) Money that she saves to the money she spends = 50,000 : 2,00,000 = 1 : 4
Example 7: Out of 2,000 students in a school, 750 opted for basketball, 800 opted for cricket and
the remaining opted for table tennis. If a student can opt for only one game, find the
ratio of:
(a) number of students who opted for basketball to those who opted for table tennis.

(b) number of students who opted for cricket to those who opted for basketball.
(c) number of students who opted for basketball to the total number of students.
Solution: Total number of students = 2,000
Number of students who opted for table tennis = 2,000 – (800 + 750) = 450
(a) Number of students who opted for basketball to the number of students who
opted for table tennis = 750 : 450 = 5 : 3
(b) Number of students who opted for cricket to the number of students opted for
basketball = 800 : 750 = 16 : 15
(c) Number of students who opted for basketball to the total number of students
= 750 : 2,000 = 3 : 8

Example 8: The cost of a dozen calculators is ` 720 and the cost of 7 pilot pens is ` 315. Find
the ratio of the cost of a calculator to the cost of a pilot pen.

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