Penelope baked 5 trays of shortbreads. There were 20 shortbreads in each tray. She gave ¹₄ of the shortbreads to her pupils and ²₅ of the remainder to Japheth. She then packed the rest of the shortbreads equally into 9 packets. How many shortbreads were there in each packet?
Total number of shortbreads that Penelope baked
= 5 x 20
= 100

Fraction of the shortbreads left after Penelope gave to her pupils
= 1 - ¹₄ 
=  ³₄ 

Number of shortbreads left after Penelope gave to Japheth
= ³₄ x 100
= 75 

Fraction of the remaining shortbreads left after Penelope gave to Japheth
= 1 - ²₅ 
=  ³₅ 

Number of shortbreads that Penelope packed into 9 packets
= ³₅ x 75
= 45

Number of shortbreads in each packet
= 45 ÷ 9
= 5

Answer(s): 5