Amber earns £7 for each hour she works from Monday to Friday. She earns £10 for each hour she works on Saturday. One week Amber worked for 4 hours on Saturday. That week she earned a total of £180 (a) How many hours did Amber work that week?

We know Amber worked 4 hours on a Saturday, so she earned 4*£10= £40 that day. The rest of the money, which is £180-£40=£140, she must have earned it during the week. Knowing she earns £7 per hour, this will give us £140:£7=20 hours. Adding up the hours during the week and the ones from Saturday, we get 20+4= 24 hours..