Bob has one sister.

1. She is 4 years older than twice Bob's age

2. The sum of their ages is 76

what is the answer?

Bob is 36

sister is 40

Step-by-step explanation:

76-4=72

72/2=36

sister is 52

bob is 24

Step-by-step explanation:

Let S = sisters age and B = Bob's age

Bob's sister is 4 years older than twice Bob's age:

mathematically : S = 4 + 2B ... eq1

the sum of their ages is 76

mathematically : S + B = 76 ... eq 2

substituting eq 1 into eq2,

S + B = 76

(4+2B) + B = 76

4 + 3B = 76 (subtract 4 from both sides)

3B = 76 - 4

3B = 72 (divide both sides by 3)

B = 72/3 = 24 (answer)

substitute value of B into equation 1

S = 4 + 2B

S = 4 + 2 (24)

S = 4 + 48

S = 52 (answer)