Answer:
Prancer spent 240$
Dasher spent 120$
Cupid spent 360$
Explanation:
Dasher = D
Prancer = P
Cupid = C
"Dasher spent half as much as Prancer"
D = 1/2P
"Cupid spent 3 times more than Dasher"
C = 3 * D
C = 3 * 1/2P
P + c + d = 720
P + 1/2p + 3*1/2P = 720
3P = 720
3P/3 = 720/3
P = 720/3
P = 240
Prancer spent 240$
Dasher spent 120$ (240/2)
Cupid spent 360$ (120*3)