How many seven-digit numbers are there when 0 and 5 cannot be the leading number?

Annie walked her dog 2 1/4 miles from her house to the dog park and 3/7/8 miles around the park. then she walked the same distance home. how many miles did she walk in all?

It is given that the quadratic equation hx²-3x+k=0, where h and k are constants, has roots [tex] \beta \: and \: 2 \beta [/tex]express h in terms of k

Events a and b are independent. the probability of a occurring is 2/5. the probability of b occurring is 1/4. what is p(a and b)?