The line graph shows the amount of money Riordan spent from July to December.

1. Of the amount Riordan spent in November, $102 was spent on food and the remaining amount was spent on transport. How much did he spend on transport in November?
2. In which month did Riordan spend $100 less than the previous month? Give your answer in this format. (Eg Jan)

(a)
Amount that Riordan spent in November = $280

Amount that Riordan spent on transport
= 280 - 102
= $178

(b)
To find a decrease in a line graph, look for a decreasing slope. 

The 2 decreasing slopes are from September to October and October to November. Now, find the month when Riordan spent $100 less than the previous month.

Amount that Riordan spent in September = $600
Amount that Riordan spent in October = $500

Amount that Riordan spent in October less than September
= 600 - 500
= $100 (✓)

Amount that Riordan spent in October = $500
Amount that Riordan spent in November = $280

Amount that Riordan spent in November less than October
= 500 - 280
= $220 (x)

The month that Riordan spent $100 more than the previous month = Oct

Answer(s): (a) $178; (b) Oct