Bicyclists Bob and Judy started at noon from points 60km apart and rode toward each other, meeting at 1:30pm. Judy's speed was 4km greater than Bob's speed. Find their speeds.
omg how do i do this!?!?
2006-09-07 15:38:49 · 2 answers · asked by islAnd_paradisex4 1 in Science & Mathematics ➔ Mathematics
Call Bob's speed s(b)
Call Judy''s speed s(j) = s(b) + 4km/h
The time elapsed before they meet is
t = 1.5h
Remember...
s=d/t or d=s*t
How far will Bob have traveled after 1.5h?
d(b) = s(b) * 1.5h
How far will Judy have traveled after 1.5h?
d(j) = s(j) * 1.5h = (s(b)+4km/h) * 1.5h
Since they began 60km apart we know the total distance they both had to travel to meet is 60km or in other words...
d(b)+d(j) = 60 km = s(b)*1.5h+(s(b)+4km/h)*1.5h
3h*s(b)+6km = 60km
s(b)+2km/h = 20km/h
so s(b) = 18km/h
and s(j) = s(b)+4km/h = 22km/h
2006-09-07 15:56:27 · answer #1 · answered by Andy S 6 · 0⤊ 0⤋
If some thing is 40% smaller, you in basic terms subtract 40%. So 40% of 40 energy is 16: you try this by technique of multiplying 40 by technique of 0.4. the answer will be 40 - 16 = 24 A shorter way would in basic terms be to multiply by technique of 40 by technique of 0.6, in view that that's a million-0.4.
2016-11-06 21:11:40 · answer #2 · answered by Anonymous · 0⤊ 0⤋