PSLE
Usha had to sew 171 shirts. She sewed 6 shirts each day from Monday to Friday and 11 each day on Saturday and Sunday. Starting on a Wednesday, on which day of the week did Usha finish sewing all the shirts? Give your answer in number. (Eg Mon = 1)
Number of weekdays that Usha sewed on the first week = 3

Number of shirts that Usha completed for from Wednesday to Sunday on the first week
= 3 x 6 + 2 x 11 
= 18 + 22
= 40

Number of shirts left to sew
= 171 - 40
= 131

Number of shirts that Usha could sew per week from second week onwards
= 5 x 6 + 2 x 11
= 30 + 22
= 52

Number of weeks that Usha needed to sew 131 shirts
= 131 ÷ 52
= 2 r 27

Number of days that Usha needed to sew 27 shirts
= 27 ÷ 6
= 4 r 3

Usha needed 1 more day to finish sewing the remaining 3 shirts.

Day of the week that Usha completed her sewing
= 4 + 1
= 5 (Fri)

Answer(s): 5