Question

Shaun is 4 years older than her sister Charmaine. If the sum of their ages is 16 how old is Charmaine?

a.4 years old
b.6 years old
c.8 years old Eliminate
d.10 years old

Answer 1

S=C+4
S+C=16 ----> S=16-C
16-C=C+4
16-4=2C
12=2C
C=6

b.6 years old

Answer 2

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Define x :
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Let Charmaine's age be x
Charmaine = x
Shaun = x + 4

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Construct equation :
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Sum of their age is 16
x + x + 4 = 16
2x + 4 = 16
2x = 12
x = 6

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Find their Charamine's and Shaun's age
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Charmaine = x = 6
Shaun = x + 4 = 6 + 4 = 10

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Answer: Charmaine is 6 years old. (Answer B)
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