A sports shop had 400 ping pong balls for sale. Each ping pong ball is sold at $2. At the end of each day, the number of ping pong balls sold was recorded in the bar graph shown.

1. What fraction of the total number of ping pong balls was left at the end of Day 3? Express your answer in its simplest form.
2. If the shop decided to sell every 4 ping pong balls at $5 from Day 4 onwards, how much less would it collect from the sale of the ping pong balls?

(a)
Number of ping pong balls left at the end of Day 3
= 400 - 44 - 76 - 64
= 216

Fraction of ping pong balls left at the end of Day 3
= ²¹⁶₄₀₀
= ²⁷₅₀

(b)
Number of ping pong balls sold from Day 4 to Day 6
= 48 + 60 + 76
= 184

Amount that it would collect if it sold the 184 ping pong balls at the original price
= 184 x 2
= $368

Number of sets of 4 ping pong balls
= 184 ÷ 4
= 46

Amount that it would collect if it sold the 184 ping pong balls at every 4 ping pong balls at $5
= 46 x 5
= $230

Amount that it would collect less  from the sale of the ping pong balls
= 368 - 230
= $138

Answer(s): (a) ²⁷₅₀; (b) $138