Question

Kevan is 6 years younger than his sister Katie. Melanie is twice as old as kevan. How old are all three siblings?

A. If you let K represent Katie's current age, what expression can you use to represent kevan's current age?
B. Based on your answer to part a, what expression represents Melanie's age?
C. If Melanie is 18 years old , what equation can you write to solve the problem?
D. Solve the equation. How old are kevan and Katie?

Answer 1

A- k-6

B- 2(k-6)

C- 18 = 2 (k-6)

D- katie- 15, kevan 9

Explanation:

Answer 2

A:
k=katie's age
ke=kevan's age=k-6 (Kevan is 6 years younger than his sister Katie)

B:m=Melanie's age=2*ke=2k-12 (Melanie is twice as old as kevan)

C and D: M=18

so this means that

18=2*ke
if we divide both by 2, we get:
9=ke
Kevan is 9 years old

and 18=2k-12

add12 to both sides:
30=2k
15=k
Katie is 15 years old