Given:
John had to pay a combined electric and gas bill $150.
The electric portion of the bill was $90.
To find:
The ratio of money spent on electric to that on gas.
Solution:
Let x be the amount of gas bill.
The electric portion of the bill was $90 and John had to pay a combined electric and gas bill $150. So,
[tex]90+x=150[/tex]
[tex]x=150-90[/tex]
[tex]x=60[/tex]
The gas portion of the bill was $60.
The ratio of money spent on electric to that on gas is:
[tex]\text{Required Ratio}=\dfrac{\text{Electric bill}}{\text{Gas bill}}[/tex]
[tex]\text{Required Ratio}=\dfrac{90}{60}[/tex]
[tex]\text{Required Ratio}=\dfrac{3}{2}[/tex]
[tex]\text{Required Ratio}=3:2[/tex]
Therefore, the ratio of money spent on electric to that on gas is 3:2.