Question

Robert is 10 years older than her brother. In 2 years, Robert will be three times as old as his brother. How old are they now?

Answer 1

Brother is 3 and Robert is 13

Explanation:

R= roberts age

B = brothers age

R = B+10

In 2 years, so we add 2 to each age

(R+2) = 3(B+2)

We now have 2 equations and 2 unknowns

Substitute R = B+10 into the second equation

(B+10+2) = 3(B+2)

Combine like terms

(B+12) =3( B+2)

Distribute the 3

B +12 = 3B+6

Subtract B from each side

B-B +12 = 3B-B+6

12 = 2B+6

Subtract 6 from each side

12-6 = 2B +6-6

6 = 2B

Divide by 2

6/2 = 2B/2

3 =B

Brother is 3

Now we need Roberts age

R = B+10

R = 3+10

R =13