Some friends are chatting about what films they have watched over the weekend.
Alice, Hayden and Lisa each watched a different film on Sunday night.
Alice’s film is thirty minutes longer than Lisa’s film.
Hayden’s film is twice as long as Lisa’s film.
Altogether the films last 390 minutes.
How long is each of their films?
Answer:
Let A = Alice’s film length, H = Hayden’s film length, L = Lisa’s film length
A = L + 30
H = 2L
A + H + L = 390
Substituting the first two equations into the third:
(L + 30) + 2L + L =390
4L = 360
So L = 360/4 = 90
Substituting L back into the first equation:
A = 90 + 30 = 120
Substituting L back into the second equation:
H = 2 x 90 = 180
So:
Alice = 120 (minutes) Hayden = 180 (minutes) Lisa = 90 (minutes)