What is 6c3? as in, how many ways can you choose 3 objects out of 6 objects, where order does not matter?

If ac = 12 and ab=7 is it possible that bc =10

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?

The distance between two points is 6.5cm and scale of map is 1: 1000 what's the distance between the two points