R + b = 21
2b = r
now we sub eq 2 into eq 1
r + b = 21
2b + b = 21
3b = 21
b = 21/3
b = 7
2b = r
2(7) = r
14 = r
so there are 7 bluejays (b) and 14 robins (r)...for a total of 21
factorising the first denominator
x²-2x-3 = x² -3x+x-3 = (x+1)(x-3)
(a) 
finding LCD
(b) LCD of (x-3)(x+1) and (x-3) is (x-3)(x+1)
(c)
(d)
Answer:
Number of minutes per lap = 2.25 minute
Number of lap per minute = 0.444 lap (Approx)
Time taken for 15 lap = 33.75 minutes
Step-by-step explanation:
Given:
Number of laps = 4
Time taken = 9 min
Computation:
Number of minutes per lap = 9 / 4
Number of minutes per lap = 2.25 minute
Number of lap per minute = 4 / 9
Number of lap per minute = 0.444 lap (Approx)
Time taken for 15 lap = 15 x 2.25
Time taken for 15 lap = 33.75 minutes
