Answer:
$1 is a missing due to the addition of unrelated amounts.
$(20 - 1)×3 + $2
Can never be equal to
$20 × 3
Step-by-step explanation:
The statement in a nut-shell is
- The three friends paid $20 each initially, to make $60.
- $1 each was returned to them, so that they reduced the expenses, and paid $19 each, to make $57.
- They tipped a man $2.
WHY IS $57 + $2 ≠ $60?
That was so, because the amounts that were added weren't related.
If their total spending was what they wanted to calculate, it should have included the amount in the receipt of $55 payment received from the hotel.
The right calculation should have been:
$55 payment to the hotel
+
$3 change the three friends received ($1 each)
+
$2 tip they gave.
=
$60
