Question

*5. Gina's sister is 9 years older than Gina. Their combined ages add up to

49. How old is Gina? *
A. 29 years
B. 20 years
C. 19 years
D. 9 years

Answer 1

Answer: B. 20 years

Explanation:

we will represent Gina sister's age by x and Gina's age by y.

Now were know that the age of Gina sister is 9 years older than Gina's so we can represent that by the equation x = y + 9

If we add their ages it is 49 so we can also represent that by the equation,

x + y = 49.

x = y + 9

x + y = 49

Using both equations, substitute x in the first equation into the second equation and solve for y.

(y + 9) + y = 49 solve for y , by first combining like terms.

2y + 9 = 49 subtract 9 from both sides

-9 -9

2y = 40 divide both sides by 2

y = 20

Since y was used to represent the age of Gina then Gina will be 20 years old.

Answer 2

B. 20 years

Explanation:

By using the process of trial and error, if Gina is 20 years old, that would mean her sister is 29 years old. This is because 20+9 is equal to 29. 29+20 sums up to 49.