(a) 30%

**(b) 70%**

(c) 100%

(d) 250%

Explanation:

Let C.P.= Rs. 100. Then, Profit = Rs. 320, S.P. = Rs. 420.

New C.P. = 125% of Rs. 100 = Rs. 125

New S.P. = Rs. 420.

Profit = Rs. (420 – 125) = Rs. 295.

Required percentage = (295/420) x 100 % = 1475/21 % = 70% (approximately).