a jersey has two digit number. in how many ways can the number be arranged if a)no double digit is allowed b)double digit are allowed​

a) 90

b) 100

Step-by-step explanation:

This is a probability problem. In order to solve it, we must multiply the number of possible numbers by eachother.

a) the first digit can be any number between 0 and 9. That's 10 options. The second digit must be different from the first one: that's 9 options. 10x9=90

b) the first digit can be any number between 0 and 9. That's 10 options. The second digit can also be any number between 0 and 9. That's also 10 options. 10x10=100

f

step-by-step explanation:

f

80° is the measure of gh

step-by-step explanation:

circle f is congruent to circle j

we have two circle with center f and j.

both circles are congruent. the radius of the circle would be equal.

see the attachment for the circle.

we are given ∠efd ≅ ∠gjh

therefore, arc (ed) = arc (gh)     (∴ circle f is congruent to circle j)

but ∠dfe=80°=arc (ed)

therefore, arc (gh) = 80°

thus, 80° is the measure of gh