Points Q, R, and S are on a line segment so that R is between Q and S. If QR = 4RS, what percent of QS is QR?
There are 28 students in a math class and 23 students in a chemistry class. If eight of these students take both math and chemistry, what is the ratio of the number of students taking only chemistry to taking only math?
2007-08-05 15:24:23 · 4 answers · asked by ? 2 in Science & Mathematics ➔ Mathematics
80% and 3/4
2007-08-08 10:32:04 · answer #1 · answered by Anonymous · 0⤊ 0⤋
If QR = 4RS, QR is 4/5 of QS and RS is 1/5 of RS. So QR is 80% of QS.
20 students are taking only math. 15 students are taking only chemistry. The ratio is 15:20 = 3:4.
2007-08-05 22:28:18 · answer #2 · answered by DavidK93 7 · 0⤊ 0⤋
28-8=20
23-8=15
The ratio would be 20:15 There are also two other ways of writing ratios and they are 20/15 and 20 to 15. They all mean the same thing.
I don't know the first one though.
2007-08-05 22:29:54 · answer #3 · answered by ? 4 · 0⤊ 0⤋
qr=4rs
qr+rs=qs change this to
qr=qs-rs now substitute into first equ.
qs-rs=4rs
qs=5rs
substitute into 2nd equ to get
qr=5rs-rs
qr=4rs
set qr over qs to get
(4rs)/((5rs)
cancel the "rs" to get
4/5 which equals 80%
2007-08-05 22:36:35 · answer #4 · answered by kelsey 7 · 0⤊ 0⤋