X - the number of pencils
y - the number of pens
She has twice as many pencils as she has pens.

Tom borrows a pen, so she has y-1 pens. Now she has ten less pens than pencils.

Set 2y and y+9 equal to each other:
She has 9 pens.
Answer:
15
Step-by-step explanation:
3*6 - 6/2
18 - 3
15
9514 1404 393
Answer:
$2.98
Step-by-step explanation:
The amount of interest earned is ...
I = P((1 +r)^t -1)
I = $9(1.1^3 -1) ≈ $2.98
Daniel will earn about $2.98 in interest in 3 years.