A fruit seller had some apples. He sells 40% apples and still has 420 apples. Originally, he had:

(a) 588 apples

(b) 600 apples

(c) 672 apples

(d) 700 apples

Suppose originally he had X apples.
Then, (100 – 40)% of X = 420.
60/100 x X = 420
X = (420 x 100)/60 = 700.