Question

As of January 2012, the top three grossing pictures worldwide were Avatar, Titanic and the finalenof Harry Potter series. Together they grossed $5.9 billion. Avatar earned just $300,000,000 less than both other movies combined, while Avatar and Titanic together were $600,000,000 less than four times Harry Potter. How much has each movie grossed?

Answer 1

Avator--- a
Titanic --- t
Harry Potter -- p

let's just reduce all monies to millions
a+t+p = 5900 **
a = t+p-300 ---> a-t-p = -300 ***
a+t= 4p - 600 --- a+t-4p = -600 ****

add** and ***
2a = 5600
a = 2800

add *** and ****
2a - 5p = -900
5900 - 5p = -900
-5p = -6500
p = 1300

back in **
2800 + t + 1300 = 5900
t = 1800

a=2800, t=1800, p=1300

Switch back to millions

Answer 2

in hundred millions

A + 3 = T + H
A + T + 6 = 4 H
A + T + H = 59

so
3 - T - 6 = T - 3 H
6 - H = 4 H -59
5 H = 65
H = 13

- T - 3 = T -3(13)
36 = 2 T
T = 18

A + 3 = 13 + 18
A = 28

so
A 2, 800, 000, 000
H 1, 300, 000, 000
T 1, 800, 000, 000