The Least Common Multiple (LCM) of 8 and 4 is 8. Multiply the numerator and denominator of each fraction by whatever value will result in the denominator of each fraction being equal to the LCM:
1/8 + 3/4= 1/8 +<u> 3 x 2 </u> = 1/8 + 6/8
4 x 2
Now that the fractions have like denominators, add the numerators:
#1. Let x be the number of hours spent dog walking, then the amount of money earned dog working is 12x. #2. Let y be the number of hours spent washing cars, then the amount of money earned washing cars is 18y. #3.