On the first day read one-quarter of a novel second day, you read half of the remaining pages. On the third day, you read the last 120 pages of the novel

Question

i don't know how to work this 

 

Answer 1

N/4 + (1/2(N-N/4) + 120 = N = total number of pages in the novel

N/4 + 3N/8 + 120 = N

N- N/4 -3N/8 = 120

N(1-1/4-3/8) = 120

N(8/8 -2/8 -3/8) = 120

N(3/8) = 120

N = 120(8/3) = 320 pages total in the novel

first you read 1/4 of 320 = 80 pages

next 1/2 of 240 remaining = 120 pages

for a total 200 pages

then you read the last 120 pages

80 + 120 +120 = 320 total pages