Answer:
option 3. 1 ¹¹/₄₀
Explanation:
3 ⁵/₈ + ( -2 ⁷/₂₀)
Multiply 3 and 8 to get 24.
24 + 8 - 2 x 20 + 7
8 20
Add 24 and 5 to get 29.
29 - 40 + 7
8 20
Add 40 and 7 to get 47.
29 - 47
8 20
Least common multiple of 8 and 20 is 40.
Convert
²⁹/₈ and ⁴⁷/₂₀ to factor with denominator 40
145 - 94
40 40
subtract their numerators
145 - 94
40
simplify:
51
40
so the final answer is 1 ¹¹/₄₀