Question

1) Mei was going to sell all of her stamp

collection to buy a video game. After
selling half of them she changed her mind.
She then bought thirteen more. How
many did she start with if she now has 25?

Answer 1

24

Explanation:

now Mei has 25 stamp collections after adding 13 more to what she remained with after selling; this means that after selling she was left with (25_13)=12

this is the half of what she had initially

this means that she initially had (12*2)=24

this gives means that she started with 24 as a stamp of her collection

Answer 2

24

Explanation:

let the starting number be x

she sold 1/2 x and has 1/2 x remaining with her

she bought 13 and has 25 now

so, 1/2x + 13 = 25

1/2 x= 25-13 = 12

hence x= 24