Statistics: Making Combinations of just a few out of a set

1. Clifford is at his local electronics store and they are having a sale on Android phone accessories. Clifford can buy up to two different accessories for $20. He has the option to purchase a case, belt clip, headphones, usb cable, vehicle charger, or screen protector. It doesn't matter which order he buys the items. How many combinations of one or two accessories are possible?

ANSWER: (D) 21

2. {1, 2, 3, 4, 5}

Using the set above, how many pairs of numbers can be chosen so that their product is less than 10?

ANSWER: 6