Banu's present age is 45 years old while Binu's present age is 25 years old.
STEP-BY-STEP EXPLANATION:
We will be using simultaneous equations to solve this problem.
Let's first establish the two equations we will be using to solve this problem.
Let Banu's present age = x
Let Binu's present age = y
Equation No. 1 -
x = y + 20
Equation No. 2 -
x + 5 = 2y
To begin with, as ( x ) is already the subject in the first equation and it is already in its simplest form, we will substitute the value of ( x ) given from the first equation into the second equation to solve for ( y ) accordingly.
Equation No. 2 -
x + 5 = 2y
( y + 20 ) + 5 = 2y
y + 25 = 2y
y - 2y = - 25
- y = - 25
y = 25
From this, we will substitute the value of ( y ) from the second equation into the first equation to solve for ( x ) accordingly.
Greg spends $0.45 on a eraser and $0.30 on a pen. How much money does Greg spend?
Well first you find the key words, (How much) which means you will be using addition in this problem. The numbers you will be adding are $0.75 and $0.30 which equals, $0.75