Answer:
he bought 13 coffee mugs and 8 key chains.
Step-by-step explanation:
How about we solve by simulataneousequation:
consider coffee mug 'x' and key chain 'y'
there are total 21 items,
x+y = 21
=> x = 21 - y .........................(i)
and
total cost is $132.50
8.5x + 2.75y = 132.5 .........(ii)
put value of x from eqn (i) into (ii):
8.5 ( 21 -y) + 2.75y = 132.50
=> 178.5 - 8.5y + 2.75y = 132.50
=> -5.75y = -46
=>y = 8
Put vaklue of y back in (i):
x = 21 - y
=> x = 21 - 8 = 13
thus, x = 13
he bought 13 coffee mugs and 8 key chains.
