Q6 of 26 Page 103

There are two motors of 5 Hp and 3Hp in a factory. The 5 Hp motor requires 20 units of electricity in 8hours. Let’s work out using the method of the Rule of Three how many units of electricity will be required if the 3Hp motor works for 10 hours.

theorem1:-


The Rule of Three is a Mathematical Rule that allows you to solve problems based on proportions. By having three numbers: a, b, c,


(a)Direct proportions rule of 3:-


if ab


c then


(b)inverse proportions rule of 3:-


if ab


c then


formula:- (i)direct method----


(ii)indirect or inverse proportions xy=k



given:- method used is called indirect or inverse proportions method



w1=5,w2=3,u1=20,t1=8,t2=10





u2=9.6 unit


More from this chapter

All 26 →
4

30 heads of people repair part of a road of a village in 15 days. Let’s work out using the method of the Rule of Three how many days it will take to repair the rest of the road if additional 10 heads of people join.

5

A pump of 5 HP can lift 36000 litres of water in 8 hours. Let’s work out using the method of the Rule of Three how long it will take to lift 63000 litres of water by a 7 HP pump.

 7

In a loom at Goplanagar 14 weavers can weave 210 sarees in 12 days. The workshop got an order to supply 300 sarees within 10days during the Pujas. Let’s work out using the method of the Rule of Three how many extra weavers have to be employed to complete the work in time.

 8

A company has got the work of unloading goods from a ship in 10 days. 280 heads of people have been employed for this purpose After 3 days it is seen that th of the work has been completed. Let’s work out using the method of the Rule of Three how many heads of people are to be engaged to complete the work in time.