MATHS HELP NEEDED EXAM TOMORROW! 50 MULITPLE CHOICE PRACTICE QUESTIONS :)

Question

anonymous · Answer

if a seller incerease  the price of his product by p%, by what percentage does he need to lower the new price to get back to the original price?
a) $$p \div (1-p \div100)$$
b) p
c)$$100p \div(100-p)$$
d) $$100p \div(100+p)$$

anonymous · Answer

step by step working please :)

shubhamsrg · Answer

let original price be x
after inc, new price = x + (p% of x) = x+ px/100 = x( 1+ p/100)
now you want to get back to original price i.e. x
% dec = (x-x(1+ p/100)) / (x(1 + p/100) *100
          =(1 - 1 + p/100) / ( 1 + p/100) *100
           = (p/100+p) * 100
hope it helps../

anonymous · Answer

thanks shubhamsrg, my percentage was wrong, i just wrote it as p% :)

shubhamsrg · Answer

nevermind,,glad to help ^_^

anonymous · Answer

in order to paint a cube, 1 liter paint is needed. the cube is cut into 27 identical cubes. how much paint is needed to paint the 27 little cubes?
a)1L b)3L c)9L d)27L

anonymous · Answer

@Vincent-Lyon.Fr

vincent-lyon.fr · Answer

1 big cube of length a has area 6a² to be painted
27 small cubes of length ....  have total area of 27 x ....  to be painted.

Then direct proportionality should help you find the answer is 3 L.

anonymous · Answer

@Vincent-Lyon.Fr  thank you!