Q14 of 26 Page 103

Let’s make mathematical problems with help of given relations and find out their solutions by the Rule of Three-


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=,p1=20,p2=?,d1=8,d2=10




p2 =15


More from this chapter

All 26 →
11

A ship takes 25 days to sail from Kolkata to Cochin. The ship started with 36 sailors for each of which 850 gm of food was allotted. But the ship rescued 15 sailors from anothersinking-ship after 13 days of journey and the ship reached Cochin in 10 days increasing the speed. Let’s work out using the method of the Rule of Three what will be the quantity of food to be consumed by of each sailor to each Cochin safely and the entire storage of food would be consumed by this time.

 12

36 heads of people of a certain village can construct 12- metres of raod working 6 hours daily in 12 days. Another 6 heads of people are involved in this work and the duration of work of each day is increased by 2 hours. Let’s work out using the method of the Rule of Three the length of road to be constructed in 9 days.

 13

250 heads of people can dig a pond of size 50 meters long, 35 metres wide and 5.2 deep in 18 days by working 10 hours daily.Let’s work out using the method of the Rule of Three how many days it will take for 300 people to dig a pond of size 65 metres long, 40 metres wide and 5.6 metres deep by working 8 hours daily.

 14 B