S = Present Sam's age
B = Present brother's age
Sam is one-third as old as his brother mean:
S = B / 3
After six year Sam will be S + 6 years od.
Brother will be B + 6 years old.
In six years Sam will be one-half as old mean:
( S + 6 ) / ( B + 6 ) = 1 / 2
Now you must solve system of 2 equations with 2 unknows:
S = B / 3
( S + 6 ) / ( B + 6 ) = 1 / 2
Try solve this.
The solutions are :
S = 6 years old
B = 18 years old
Proof:
S = B / 3 = ( 1 / 3 ) B
S / B = 6 / 18 = 6 / ( 6 * 3 ) = 1 / 3
( S + 6 ) / ( B + 6 ) = ( 6 + 6 ) / ( 18 + 6 ) = 12 / 24 = 12 / ( 12 * 2 ) = 1 / 2
Sam is one-third as old as his brother. In six years Sam will be one-half as old. How old is Sam now?
2 answers
Pat had 5 snowballs less than Sam