PSLE
Riordan and Charlie were paid a total of $4140 for a job they did. Riordan was paid $1500 more than Charlie.

1. How much was Charlie paid for the job?
2. Riordan and Charlie were paid based on the number of days they worked. Riordan worked 2 times as many days as Charlie. Charlie was paid $15 less than Riordan per day. How many days did Riordan work? 

(a)
Amount that Charlie was paid = 1 u
Amount that Riordan was paid = 1 u + 1500

Total amount paid
= 1 u + 1 u + 1500
= 2 u + 1500

2 u + 1500 = 4140
2 u = 4140 - 1500
2 u = 2640

1 u = 2640 ÷ 2 = 1320

Amount that Charlie was paid
= 1 u
= $1320

(b)
Amount that Riordan was paid
= 1 u + 1500
= 1320 + 1500
= $2820

Riordan worked 2 times as many days as Charlie.

2 sets of Riordan's salary = $2820

1 set of Riordan's salary
= 2820 ÷ 2
= $1410

1 set of Charlie's salary = $1320

Difference between each set of Riordan's and Charlie's salaries
= 1410 - 1320
= $90

Number of days in 1 set
= 90 ÷ 15
= 6

Number of days that Riordan worked
= 2 x 6
= 12

Answer(s): (a) $1320; (b) 12