human
Read values off a real life graph Lethna pays at one rate for the first \( 100 \) units of electricity she uses. She pays at a different rate for all the other units of electricity she uses.

How much must she pay for using a total of \( 800 \) units of electricity? ![A graph showing how the cost changes for different numbers of units. The first 100 units cost £0.25 per unit. Then the rate changes to £0.10 per unit.]() \( £ 110 \)
gpt
Thinks terms in linear sequence are in direct proportion