Question

12) There is enough paint in the painting box for painting the area of 0.82m2. If
an eraser is of dimensions 2cm x 1cm x 0.7cm. Then how many such
erasers can be painted using this paint box.​

Answer 1

Given :-

• The painting box can paint the area of 0.82m².
• Dimensions of an eraser = 2cm x 1cm x 0.7cm.

To Find :-

• How many such erasers can be painted using this paint box. ?

Solution :-

→ Dimensions of an eraser = 2cm x 1cm x 0.7cm.

Eraser is in the form of a cuboid . So , while painting, whole 6 faces should be paint .

So,

→ Total surface area of an eraser = 2(L * B + B * H + H * L)

Putting values we get,

→ TSA of an eraser = 2(2*1 + 1*0.7 + 0.7*2)

→ TSA of an eraser = 2(2 + 0.7 + 1.4)

→ TSA of an eraser = 2 * 4.1

→ TSA of an eraser = 8.2 cm².

Now,

→ 1m² = 10000cm².

So,

→ Total area can be painted with box of paint = 0.82 * 10000 = 8200 cm².

Therefore,

→ Total number of eraser can be painted with box = (Total area can be painted) / (Total area of an eraser) = 8200/(8.2) = (82000/82) = 1000 Erasers. (Ans.)

Hence, 1000 such erasers can be painted using this paint box.