Ma2a Assignment 2 Area: Algebra,

1. Kristina fills the car with 23 liters of petrol. In addition, she buys 8 apples at the petrol station. Draw an expression for how much she gets back in the cash register if the petrol costs SEK u/litre, if the apples cost SEK v/pc. and if she pays with a 500 note.

2) A mobile phone company charges the following fees from its customers: () = 6 + 150 where () is the monthly cost in kroner when calling for x minutes.

a) Calculate and explain in words what A(0) means.

b) Calculate and explain in words what A(180) means.

c) A customer paid 360 kroner a month. How many minutes did the customer call that month?

3) Olle bought 3 kg of potatoes and 2 kg of apples in a grocery store and had to pay 39.10 kroner. In the same store, Fia bought 7 kg of apples and 4 kg of potatoes for 94.60 kroner. How much did the potatoes and apples cost per kg?

4) During World War II, American soldiers would blow up a bridge with dynamite and barbed wire. They needed a safety distance to avoid injuring themselves and therefore used a stubby wire that was 1120 meters long and which they knew burned at 0.9 meters per second. a) Set up a formula that shows how much of the stub wire, y meters, remains until the bridge after x minutes. b) How long will it take from the ignition of the stub wire to the explosion of the bridge? Answer in minutes and seconds.