Mr Lee spent $5190 on some watches and clocks. The amount spent on watches was $2310 more than the amount spent on clocks. He bought 4/5 times as many clocks as watches.
Each clock cost $13 less than each watch. What was the total number of watches and clocks bought by Mr Lee?
Amount spent on clocks = (5190 - 2310)/ 2 = 1440
Amount spent on watches = 1440 + 2310 = 3750
Most students should be able to do the above steps.
The important thing is to find the cost of 1 unit of both watches and clocks for comparison.
4/5 as many clocks as watches means clocks equal to 4 units while watches equal to 5 units.
Cost of 1 unit of clocks = 1440 / 4 = 360
Cost of 1 unit of watches = 3750 / 5 = 750
Difference between 1 unit of clock and watches = 750-360 = 390
Number of watches or clocks in 1 unit = 390 / 13 = 30
Hence total ( 9 units of clocks and watches ) = 9 x 30 = 270
