Answer:
44 ten-dollar bills
Explanation:
Assume that all 124 bills are ten-dollar bills,
124 x $10 = $1240
Total Value of Money : $840
$1240 - $840 = $400
There are $400 worth of five-dollar bills,
$400 / 5 = 80 (The number of five-dollar bills)
Therfore the number of ten-dollar bills,
124 - 80 = 44
Let's check:
44 x $10 = $440
80 x $5 = $400
Total = $440 + $400
= $840