In a group of 30 students, 20 take french, 15 take spanish, and 5 take neither language. How many students take both french and spanish?.

10

Step-by-step explanation:

a+b+c+d=30(1)

b+c=20(2)

c+d=15(3)

a=5

subtract equation 2 from equation 1.

a+d=10

since a=5, d=5

substituting 5 for d in equation 3 leaves c=10

2.2°  

step-by-step explanation:

let θ = the angle of elevation.

tanθ =77/2020

tanθ = 0.038 12

      θ = tan⁻¹0.038 12

      θ = 2.2°