Answer:
The train was travelling at 60 km/h
Step-by-step explanation:
We're already given time and distance, and speed is just distance/time, so:
240km / 4h
= (240/4) km/h
= 60km/h
Answer:
21,375
Step-by-step explanation:
142,500 multiplied by 15 % is your answer. at least I hope
Answer: x = 8√7, y = 4√21
Explanation:
1) There are three triangles.
2) The small triangle of the right has a right angle, and the sides are the height, x and 16.
3) The small triangle of the left, has a righ angle, and the sides are the heigth, y and 12.
4) The big triangle has a right angle, and the sides are the x, y and 28.
5) Set three equations using Pytagora's theorem for the three triangles..
a) y^2 + x^2 = 28^2 = 784
b) h^2 + 12^2 = y^2
c) h^2 + 16^2 = x^2
6) Subtract b) from c)
16^2 - 12^2 = x^2 - y^2
=> x^2 - y^2 = 112
add x^2 - y^2 = 112 with the equation a)
x^2 - y^2 = 112
x^2 + y^2 = 784
----------------------
2x^2 = 112 + 784
2x^2 = 896
x^2 = 896 / 2 = 448
x = √448
x = 8√7
7) now you can use any a) to find y:
y^2 + x^2 = 784
=> y^2 = 784 - x^2
=> y^2 = 784 - 448
=> y^2 = 336
=> y = 4√21
Answer: x = 8√7, y = 4√21
