Answer:
Option A
Explanation:
Sarah took 4 days to write a paper.
She wrote 12 pages per day, so total number of pages she wrote in 4 days = 12 × 4
= 48 pages
On day 1, she wrote number of pages = 12
On day 2, she wrote number of pages = 15
On day 3, she wrote number of pages = 9
On day 4, she wrote number of pages = P
She wrote total number pages in 4 days = 12 + 15 + 9 + P
= 36 + P
Therefore, P + 36 = 48
P = 48 - 36
P = 12
She wrote 12 pages on day 4.
Option A is the answer.