Two fifths of a number is 36.What is half of that same number?

Answer 1

To summarize how we figure this one out, we are told that 'the number' is two-fifths of thirty-six, then in the next statement asked what half of that number is. Start by representing this statement mathematically using the letter 'x' as the place holder for 'the number' -

2/5(x) = 36

First, multiply both sides of the equation by the value of five to remove the fraction's denominator -

5(2/5)(x) = 36(5)

Applying basic algebraic rules and processes, the five on the left side cancels with the denominator leaving the coefficient of 'x' as two, and the right side of the equation can be calculated to find a quantity of 180. So, we have simplified this down to -

2(x) = 180

Dividing both sides of the equation by two, we can solve for the value of 'x' -

2((x)/2) = 180/2

Leaves us with -

x = 90

Now that we know that 'x' is ninety, we can say that 'the number' is ninety.

Knowing this, we are asked to find half of 'the number'. So, we can simply divide the number by two to find 'the answer', which is a different quantity than the number that we will label 'y' in this case -

y=x/2

where 'x' is now known to be the quantity of ninety, we can substitute 90 for 'x':

y=90/2

reduces to y = 45

Since we used 'y' to represent 'the answer', that answer is 45.

Answer 2

45