D
7•4 =28, -5•0 =0... 28+0=28
Answer:
242 cm
Step-by-step explanation:
1. Find the scale factor
A scale factor (SF) is the ratio of two corresponding lengths in similar figures.
SF = actual distance/scale distance
If the scale width is 3.8 cm,
SF = 418 cm/3.8 cm = 110
2. Calculate the actual depth
110 = actual depth/2.2 cm
Actual depth = 110 × 2.2 cm = 242 cm
Answer:
Speed of river's current = 5 mph
Step-by-step explanation:
Let 'd' be the distance covered
Let x be the speed of the rivers current
Speed upstream = 15-x
speed downstream = 15+x
Time = distance / speed
time upstream = 
time downstream = 
the ferry trip upstream takes twice as long as its return trip downstream
= 
divide both sides by d
= 
cross multiply


Add 2x on both sideds

subtract 15 from both sides and divide by 3

x=5
Speed of river's current = 5 mph