Mary puts some money in boxes, A, B, C and D. The amount of money in box A is 2/7 of the total amount of money in boxes B, C and D. The amount of money in box B is 2/3 of tho total amount of money in boxes A, C and D. The amount of money in box C is 1/3 of the total
amount of money in boxes A, Band D. If there is $161 in box D, what is the total amount of money in the four boxes?
The amount of money in box A is 2/7 of the total amount of money in boxes B, C and D
a = (2/7)(b+c+d)
7a = 2b + 2c + 2d , d = 161
7a = 2b + 2c + 322 ---> 7a - 2b - 2c = 322
The amount of money in box B is 2/3 of tho total amount of money in boxes A, C and D
b =(2/3)(a+c+d)
3b = 2a + 2c + 322 ---> 2a - 3b + 2c = -322
The amount of money in box C is 1/3 of the total
amount of money in boxes A, Band D
c = (1/3)(a+b+d)
3c = a + b + 161 ---> a + b - 3c = -161
Use your favourite method to solve the 3 equations in 3 unknowns
Hint( c = 315)