假设原来有x人,每个人出y元.
则:
xy = (x-10)(y+1) ==> xy = xy-10y+x-10 ==> x-10y=10
xy=(x-10-15)(y+3) ==> xy = xy -25y+3x-75==> 3x-25y=75
根据上面的两个方程得到:
y=9
x=100
所以原来有100人参加.
假设原来有x人,每个人出y元.
则:
xy = (x-10)(y+1) ==> xy = xy-10y+x-10 ==> x-10y=10
xy=(x-10-15)(y+3) ==> xy = xy -25y+3x-75==> 3x-25y=75
根据上面的两个方程得到:
y=9
x=100
所以原来有100人参加.