DS - Percent (rated difficult)

[karthikpandian19]

On a camping trip, x campers each paid y dollars for food. What percent of the total food expenses did each camper pay?

(1) If there were one fewer camper, each camper would owe 1 dollar more.
(2) If there were half as many campers, each camper would owe 7 dollars more.

[sam2304]

# campers = x
# Amount = y

total amount be xy

y/xy = ?

1. (x-1)(y+1) = xy

xy + x - y - 1 = xy
x - y = 1

We cannot find the individual values.

2. x/2(y+7) = xy
xy/2 + 7x/2 = xy
xy + 7x = 2xy
7x = xy
y = 7.
We don't know about x.

Combining both we know the values of x and y with which we can find y/xy.

IMO C.

[ronnie1985]

IMO (C)

[karthikpandian19]

OA is C

# campers = x
# Amount = y

total amount be xy

y/xy = ?

1. (x-1)(y+1) = xy

xy + x - y - 1 = xy
x - y = 1

We cannot find the individual values.

2. x/2(y+7) = xy
xy/2 + 7x/2 = xy
xy + 7x = 2xy
7x = xy
y = 7.
We don't know about x.

Combining both we know the values of x and y with which we can find y/xy.

IMO C.