[Harsheet Kaur]

Total products= 100

C.P(cost price) For each product =10rs

Total C.P= total products× price of each product

100×10

C.P = 1000Rs

Now,

S.P for 80 products × 80×15 =1200 Rs

S.P of 20 remaining product= 20×20 =400 Rs

Total S.P = 1200+400

=1600Rs

S.P > C.P

So it is a profit

Profit= S.P – C.P

= 1600-1000

=600

Profit %= profit/C.P ×100

600/1000 ×100

=0.6×100

=60%

Total profit= 60%

[Harsheet Kaur]

Volume of cuboid = l×b×h

Base area = l×b

Now,

l×b×h =900cm3. (Eq1)

While,

l×b= 180cm2 (Eq2)

Divide (Eq1) by (Eq2)

l×b×h/ l×b = 900/180

h= 5cm