David have RM 180 and Maria had RM 55. their aunt give them same amount of money. David have twice as much money as Maria. how much money did their aunt give?
When their aunt give them x amount of money, David have RM 180 + x
Maria have RM 55 + x
David have twice as much money as Maria mean:
( 180 + x ) / ( 55 + x ) = 2
Multiply both sides by 55 + x
180 + x = 2 ∙ ( 55 + x )
180 + x = 2 ∙ 55 + 2 ∙ x
180 + x = 110 + 2 x
Subtract x to both sides
180 + x - x = 110 + 2 x - x
180 = 110 + x
Subtract 110 to both sides
180 - 110 = 110 + x - 110
70 = x
x = 70
Their aunt gave it RM 70
Proof :
( 180 + x ) / ( 55 + x ) =
( 180 + 70 ) / ( 55 + 70 ) =
250 / 125 = 2