PSLE
Bobby and Jack were paid a total of $3410 for a job they did. Bobby was paid $1840 more than Jack.

1. How much was Jack paid for the job?
2. Bobby and Jack were paid based on the number of days they worked. Bobby worked 3 times as many days as Jack. Jack was paid $15 less than Bobby per day. How many days did Bobby work? 

(a)
Amount that Jack was paid = 1 u
Amount that Bobby was paid = 1 u + 1840

Total amount paid
= 1 u + 1 u + 1840
= 2 u + 1840

2 u + 1840 = 3410
2 u = 3410 - 1840
2 u = 1570

1 u = 1570 ÷ 2 = 785

Amount that Jack was paid
= 1 u
= $785

(b)
Amount that Bobby was paid
= 1 u + 1840
= 785 + 1840
= $2625

Bobby worked 3 times as many days as Jack.

3 sets of Bobby's salary = $2625

1 set of Bobby's salary
= 2625 ÷ 3
= $875

1 set of Jack's salary = $785

Difference between each set of Bobby's and Jack's salaries
= 875 - 785
= $90

Number of days in 1 set
= 90 ÷ 15
= 6

Number of days that Bobby worked
= 3 x 6
= 18

Answer(s): (a) $785; (b) 18