A departmental store had 160 vacuum cleaners for sale during a 7-day period. The line graph shows the number of vacuum cleaners left unsold at the end of each day. The number of vacuum cleaners left unsold at the end of Day 7 was not shown.
- On which day was the greatest number of vacuum cleaners sold? Give your answer in number. (Eg 1)
- The average number of vacuum cleaners sold for the last three days was 18. How many vacuum cleaners were sold on Day 7?
(a)
To find the greatest increase in the number of tickets sold, look for the steepest decreasing slope.
On Day 4, the number of vacuum cleaners sold was the greatest number.
(b)
Total number of vacuum cleaners sold for the last three days
= 3 x 18
= 54
Total number of vacuum cleaners sold on Day 5 and Day 6
= 15 + 15
= 30
Total number of vacuum cleaners sold on Day 7
= 54 - 30
= 24
Answer(s): (a) 4; (b) 24