How many ways can a president, vis-president and treasurer be selected from a group of 15 students?

455ways

Step-by-step explanation:

This is expressed as 15 C 3 ( C- combination)

The concept of combination is used when we talk about selection.

Now we are selecting 3 from a sample of 15

15 C 3 = 15! / (15-3)! 3! = 15 ×14×13×12!/12!×3×2

= 5 × 7 × 13 = 455ways

a) 7x=7

step-by-step explanation:

the answer is b: 18

step-by-step explanation:

use the pythagorean theorem to .

a^2+b^2=c^2

plug 18 for "r"

the 2 legs are 18 and 24

18^2+24^2=c^2

324+576=c^2

900=c^2

c=30

30-12=18

18 is the radius

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