Question

7. Jennifer is 6 years older than Sue. In 4 years, she will be twice as old as Sue was 5 years ago. Find their ages

Answer 1

Answer: Sue is 20 and Jennifer is 26

Step-by-step explanation:

Let's say that J=Jennifer's age now and S=Sue's age now.

We know that:

J=S+6

Because Jennifer is 6 years older than Sue.

We also know that when Jennifer is 4 years older (J+4), she will be twice as old as Sue was 5 years from now (S-5).

So we get the following equation from that information:

J+4=2(S-5)

So we have the two equations:

J+4=2(S-5)

J=S+6

Let's substitute J=S+6 into the first equation (note that RHS means Right Hand Sie and LHS means Left Hand Side):

(S+6)+4=2(S-5)

S+10=2S-10 [Add 6+4 on the RHS, and distribute on the LHS]

S=2S-20 [Subtract 10 from both sides]

-S=-20 [Subtract 2S from both sides]

S=20 [Divide both sides by -1]

So we know S, which is Sue's age, is 20. So Sue is no 20 years old.

Finding Jennifer's age now is simple. We know Jennifer is 6 years older than Sue, and Sue is 20, so Jennifer is 26 years old.