Question

The floor of an office has dimensions 5 mx 3 m. The cost of painting the walls and ceiling is 7,440 at the rate of 60/m². Find the height of the room (in m). (rounded off to one decimal place)

• A. 6.8
• B. 4.5
• C. 3.5
• D. 5.6

Answer 1

Answer:

A. 6.8

total area= wall area + ceiling area

=2(lh+bh)+lb

total cost = 7440

rate per area = 60

so the total area $= 7440/60=124$ $m^2$

ceiling area $= lb=5\times3=15$

the final area $=124-15=109$

wall area $= 2(lh+bh)=109$

$=2(5h+3h)=109$

$16h=109$

$h=6.81$