2777

This is an icosahedron which has 20 faces.

To calculate the surface area just calculate the surface area for one face then multiply it by 20.

Surface area of one face is (area of triangle+area of the sides of the rectangular hole)

which is=> 110.84cmsq (triangle)+ 28cmsq (area of sides of the hole)= 138.84cmsq

Multiplying it by 20= 2776.8

Approximately 2777

21.5

ans:58

last horizontal row : 6 bricks needed

two horizontal rows before last combined need 30 bricks

the closest row needs 20 bricks

tip to solve: visualize and add bricks mentally , look at length and breadth . the figures height : 5 bricks . easier but time consuming way is to draw and find out- wouldnt recommend . try to solve it mentally

1. Using fossil fuels

2. Emission of greenhouse gases

3. Chlorofluorocarbons

Scroll down to the bottom of the page on home to see the weightage of all topics from 2016 in all design tests

Brilliant.org is a great website/app for maths. Philip Carter, mensa books, and Arihant books are great too.