Question

Isabel is 11 years old. This is 3 years more than twice her brother's age. How old is Isabel's brother? Let b = Isabel's brother's age.


A. 3 - 2b = 11; b = 16 years old
B. 2(11 - 3) = b; b = 16 years old
C. 2b + 3 = 11; b = 4 years old
D. 2b - 3 = 11; b = 7 years old

Answer 1

Isabel is 11 yrs old. Let Isabel's age =x
then we are told this is 3 more years than twice her brothers age.
If her brother age is b, then that equates to 2b -3
i.e x (her age)= 2b -3

Answer 2

since she is 11, 2b-3 =11
and 2b = 11 +3 = 14
b = 14/2 which equals 7
therefore her brother is 7

Answer 3

answer is D