Question

Box со

1. A man had three GH¢50,00, seven GH¢20.00 and five GH¢10.00 notes in his
pocket, if he bought a bicycle for GH¢80.00 each, how many GH¢20.00 and
GH¢10.00 notes did he have left?
​

Answer 1

The man has 6 GHc20.00 notes and 4 GHc10.00 left

Explanation:

Given

Amount = 3 GH¢50.00, 7 GH¢20.00 and 5 GH¢10.00

Spendings = GH¢80,00

Required

Determine how many GH¢20.00 and GH¢10.00 notes left

The amount he has can be represented as:

`Amount = 3 * GHc50.00 + 7 * GHc20.00 + 5 * GHc10.00`

`Spendings = GHc80.00`

This can be represented as:

`Spendings = GHc50.00+GHc20.00+GHc10.00`

Represent:

GHc50.00 with x, GHc20.00 with y and GHc10.00 with z

So, we have:

`Amount = 3 * GHc50.00 + 7 * GHc20.00 + 5 * GHc10.00`

`Amount = 3 *x + 7*y + 5*z`

`Amount = 3x + 7y + 5z`

`Spendings = GHc50.00+GHc20.00+GHc10.00`

`Spendings =x+y+z`

Subtract the spendings from the total to get amount left

`Amount\ Left= 3x + 7y +5z - (x+y+z)`

`Amount\ Left= 3x + 7y +5z - x-y-z`

Collect Like Terms

`Amount\ Left= 3x-x + 7y-y +5z-z`

`Amount\ Left= 2x + 6y +4z`

Recall that, we have represented:

GHc50.00 with x, GHc20.00 with y and GHc10.00 with z

This means that, the man has 6 GHc20.00 notes and 4 GHc10.00 left