Word Problem 64 & 65
Problem 64: Income of A is 25 % less than B’s income. How much percent B’s income would be more than that of A ?
To solve this problem we will suppose income of B
then because A’s income is 25% less than that of B, we write;
Now we can find how much B is earning extra than A – by subtracting A’s income from B’s income.
Now we use percentage formula – to find what percent this B’s extra income is of A’s income !
So, here we will put B’s extra earning as nominator and A’s income as denominator;
So, B is earning approximately 33% more than A
Problem 65: If the price of the coal be raised by 10%, by how much percent a man must reduce its consumption so as not to increase his expenditure ?
This is the problem involving percentage calculation. Here we assume that intially price of caol and expenditure are same.
i-e Let’s suppose;
Rise in price is 10%, so we will find first 10% of x (price)
New price will be the sum of increment and original price
If the man keeps on burning same quantity of coal then again his consumption will be equal to the new price
i-e he will stay with
Now suppose to keep his expenditure same (i-e ‘x’) the man now will have to reduce his consumption by y% of ‘new consumption’
Now If we subtract from ‘new consumption’ this ‘reduction’ then consumptiom will stay equal to original expenditure ‘x’
New Consumption – Reduction in Consumption = x
cancelling ‘x’ term
So, the man will have to reduce his consumption by