Answer:
Speed of the river =
km per hour
Step-by-step explanation:
Speed of the boat in still water = 4 km per hour
Let the speed of the river = v km per hour
Speed of the boat upstream = (4 - v) km per hour
Time taken to cover 6 km = 
=
hours
Speed of the boat downstream = (4 + v) km per hour
Time taken to cover 12 km =
hours
Since, time taken by the boat in both the cases is same,

6(4 + v) = 12(4 - v)
24 + 6v = 48 - 12v
12v + 6v = 48 - 24
18v = 24
v = 
v =
km per hour
(x + y = 125)3
5x - 3y = 41
3x - 3y = 375
8x = 416, x = 52
52 + y = 125, y = 73
Solution: the numbers are 52 and 73
Answer:
9/16 of the students
Step-by-step explanation:
first you can simplify 15/20 to 3/4
you can simplify 12/16 to 3/4
3/4*3/4=9/16
Answer:
Last one
Step-by-step explanation:
Imagine it as a mirror or like a paper folding in half, then figure out the direction it shifts.
Answer:
30 girls
Step-by-step explanation:
10 x 2= 20
15x2=30
For every 10 boys there are 15 girls. since 20 is just 10 multiplied by 2 you can multiply 15 by 2