Question

A part of monthly expenses of a family is constant and the remaining varies with the price of wheat. When the rate of wheat is Rs.250 a quintal,the total monthly expenses of the family are Rs.1,000 and when it is Rs.240 a quintal, the total monthly expenses are Rs.980.Find the total monthly expenses of the family, when the cost of wheat is Rs.350 a quintal.

Answer 1

when the rate of wheat is 250 /quintal ...........monthly expense is 1000
and when the rate of wheat is 240/quintal ,.........monthly expense is 980
...
from this we know that when there is a rs 10 change in price of wheat....monthly expense changes by 20 

so if the rate of wheat is 350/quintal ....the monthly income will be 1000+(10*20)..
                                                                                                        =1000+200=1200