Answer:
B and C
Explanation:
To find out if fractions A/B and C/D are equal, we can do either of 2 things:
1. Reduce them both to simple form (a form where the greatest common divisor "GCD" of numerator and denominator is 1 and the denominator is a positive integer)
2. Check if A*D = B*C, because if A/B = C/D, then we can multiply both sides by B*D, getting
A/B*B*D = C/D*B*D
A*D = C*B
We'll do the former for A and B and the latter for C and D.
Firstly, 1/4 is irreducible, because GCD of 1 and another number must be 1.
A. 3/15 = 3/(3*5) = 1/5
not equal to 1/4
B. 2/8 = 2/(2*4) = 1/4
equal to 1/4
C.
1*20=4*5
20=20
true, so 5/20 = 1/4
D.
1*40 = 11*4
40 = 44
false, so 11/40 does not equal 1/4