w= weight of marks sister
Mark weighs 74 pounds. Together, he and his sister weigh six more pounds than three times the weight of his sister. What is the weight of marks sister?
I thought of it similarly to what Robert had answered...translate the words and numbers into math language:
Mark and sister together weigh 74 + S =
Six more pounds than three times sister's weight 3S + 6
Then solve for S (sister's weight)
74 + S = 3S + 6
68 = 2S (Subtract 6 and S from both sides)
S = 34 ( Divide both sides by 2)
Sister is 34 lbs!
Let W = the weight of Mark's sister.
74+W = 3W+6
Solve for W,
W = 34 lb <==Answer