Answer: 680
Step-by-step explanation:
When order doesn't matter,then the number of combinations of choosing r things out of n = 
Given: Total participants = 17
From these, a group of 3 participants is to be tested under a special condition.
Number of groups of 3 participants chosen = 

Hence, there are 680 groups of 3 participants can be chosen,.
Answer:
3x+3
Step-by-step explanation:
Perimeter
x+x+6+x-3=3x+3
Answer:
$5
Step-by-step explanation:
Just use simultaneous equations to solve this problem.
Let cost of pens = x and cost of pencils = y:
217 x + 131 y = 913
131x + 217y = 827
Solving these 2 equations you get: x = 2 and y = 3
Hence, cost of one pen and one pencil = 2 + 3 = 5 rupees
Answer:
2 days
Step-by-step explanation:
275 miles times 0.05 = $13.75 for mileage
200-13.75=186.25 left
186.25/63.41(daily fee)= 2.93
She can rent it for 2 days