At shop A, the usual price of a mobile phone is $800. At shop B, the usual price of the same type of mobile phone is $780. During a promotion, Shop A offers the mobile phone at a discount of 20 percent and Shop B offers a discount of $120 for it. Marcus wants to buy such mobile phone.

(A) How much was the discount given by Shop A for the mobile phone?
(B) Which shop sould Marcus buy his mobile phone?

(A) The discount given by Shop A for the mobile phone can be calculated by multiplying the usual price by the discount percentage:

Discount = 20% * $800 = $160

Therefore, the discount given by Shop A for the mobile phone is $160.

(B) To determine which shop Marcus should buy his mobile phone from, we need to compare the final prices after the discounts are applied.

Shop A's final price:
Usual price - Discount = $800 - $160 = $640

Shop B's final price:
Usual price - Discount = $780 - $120 = $660

Therefore, Marcus should buy his mobile phone from Shop A as it offers a cheaper final price of $640 compared to Shop B's final price of $660.