Speed = Distance/Time. Let speed be V, distance D and time T
a)Given: D₁ =45km, V₁=x km/h
V₁=D₁/T
V₁=45/T OR T= 45/V₁
b) Given : D₂ =48 km and V₂ = V₁ + 4 km/h
V₂ = 48/T, but V₂ = V₁+4, then:
V₁+4 = 48/T OR T=48/(V₁+4). Since Time is same, then we can write:
45/V₁ =48/(V₁+4), solve for V₁:
45V₁ + 180 = 48V₁
3V₁ =180 and V₁ = x = 60 km/h
C. is the answer because -159 is a rational number
To calculate the <span>surface area of a composite figure you must apply the formulas for calculate the area of each figure that is part of the composite figure and then, you must sum all the areas calculated.
For example, is the composite figure is form by a triangle and rectangle, the surface area of the composite figure will be:
SA= Area of the triangle+ Area of the rectangle= (bh/2)+bh</span>