32
Real-life problems with charts
Textbook: Part 1, lesson 32, pp. 99–101
GoalSolve real-life problems using charts and areas.
New words
wall · devorcovering · qoplashaverage · o‘rtachaexpense · xarajat
Explanation
In a chart problem first read the needed values from the chart, then calculate. The area of a wall or floor is S = length × width (height). The amount of covering needed = total area : the area of one roll (or tile). Cost = area × price of 1 m².
Worked examples
A wall is 5 m by 3 m: S = 15 m². If one roll covers 5 m², we need 15 : 5 = 3 rolls.
Bedroom: 240 000 + 180 000 + 330 000 = 750 000 sum; hall: 150 000 + 120 000 + 280 000 = 550 000 sum. The difference is 200 000 sum.
Class activity
“Redecorate the room”: groups measure a classroom wall and work out how many rolls of wallpaper and how much money would be needed.
Practice
1
A wall is 5 m long and 3 m high. If one roll of wallpaper covers 5 m², how many rolls are needed?
3
2
A floor is 4 m by 6 m. Laminate costs 85 000 sum per m². How many sum are needed for the floor?
2040000
3
A shop sold 120, 150 and 90 loaves on three days. How many loaves a day is that on average?
120
4
240 000, 180 000 and 330 000 sum were spent on the bedroom and 150 000, 120 000 and 280 000 sum on the hall. How many sum more were spent on the bedroom?
200000