" 7.In Rohan's birthday party,"90%" of his friends came and three friends did "

In Rohan's birthday party, 90% of his friends came and three friends did not come. Find the total number of friends Rohan has

Chanti distributed (3)/(4)th of his birthday cake to his friends. Find the percentage of the cake distributed to his friends.

Arun is treating his friends for his birthday. Four of his friends opt for ice creams that cost Rs. 12 each and five of his friends choose a juice costing Rs. 8 each. How much money did Arun spend on the treat?

A person travels on a spaceship moving at a speed of 5c / 13 . (a) Find the time interval calculated by him between the consecutive birthday celebrations of his friend on the earth . (b) Find the time interval calculated by the friend on the earth between the consecutive birthday celebrations of the traveller.