Question

5 brothers want to share the cost of a birthday gift for their mom. The youngest brother is too small to get an allowance so the 4 brothers pay 3.68 dollars extra to cover for the younger brother's allowance. What is the total cost for the mother's gift

Answer 1

Answer:

Total cost=$73.60

Step-by-step explanation:

Arithmetics To Solve Simple Problems

Sometimes the use of the most basic operations can be handy to solve problems of a variety of complexities without the use of equations or algebra. We'll approach to the solution of this question by pure logic and basic operations.

If the gift was originally meant to be paid for all 5 brothers, each one would have paid one-fifth of the cost. But since the younger brother won't be paying anything, the cost will be divided among the other four brothers, each one of which will pay now one-fourth of the cost. But this new division is $3.68 more than the previous one. If we take the difference between both fractions, we get

$\displaystyle \frac{1}{4}-\frac{1}{5}=\frac{1}{20}$

That fraction is the portion of the money they are paying in excess, so the total cost should be twenty times that excess, i.e.

Total cost= 20*3.68=$73.60

Let's check. Each brother should have paid $73.60/5=$14,72. But the four brothers really paid $73.6/4=$18.40. The difference is cost is $18.40-$14,72=$3.68 as required