The answers are:
P(9, 2) = 72
P(5, 5) = 120
P(7, 7) = 5040
These are examples of permutations. The problems are asking us to find the total number of ways an event can happen.
In the first case, P(9, 2), we are asked to find the ways that 2 things can be chosen out of a group of 9.
9 x 8 = 72
P(5, 5) = 5 x 4 x 3 x 2 x 1
P(7, 7) = 7 x 6 x 5 x 4 x 3 x 2 x 1
So the answers are :
A: 5 seconds
and
B: 10 seconds
Answer:
the answer is 3 and 9. 9 is 6 greater than 3 and 9 squared and 3 squared added up give you 90.
Remark
If the lines are parallel then triangle RQS will be similar to triangle RTP
From that, all three lines in one triangle will bear the same ratio to all three lines of the second triangle.
Givens
PQ = 8
QR = 5
RS = 15
ST = x + 3
Ratio
QR/RP = RS/RT
Sub and solve
RP = 5 + 8
RP = 13
RT = 15 + x + 3
RT = 18 + x
5/13 = 15 / (18 + x) Cross multiply
5(18 + x) = 195 Remove the brackets on the left.
90 + 5x = 195 Subtract 90 from both sides.
5x = 105 Divide by 5
x = 105/5
x = 21 Answer <<<<<<<
