For every 18 eggs that Noori buys, three eggs turn out to be rotten. At the same rate, how many good eggs will Noori have if she buys 690 eggs?

Correct option is C

Given:

For every 18 eggs, 3 are rotten.

Solution:

Given that:

3 eggs are rotten and 15 eggs are good 

Rotten eggs : Good eggs = 3 : 15 = 1 : 5

Good eggs = 5/6 of all eggs

Good eggs = (5/6) of 690

=> 575 eggs

Hence, option (c) is the correct answer.