Answer:
A.6.2i-4.2 j
Step-by-step explanation:
We are given that



We have to find the projection of w on to u.
The project of vector a on b
=


Using the formula
The projection of w on to u

The projection of w on to u=6.2i-4.2j
Hence, option A is true.
Answer:

Step-by-step explanation:
Let me know if you want the full explanation. Have a great weekend! ❤

Normal-travel DATA:
distance = 240 km
rate = x km/h
time = d/r
= 240/x hrs
_______________________
Bad weather DATA:
distance = 240 km
rate = (x-20) km/h
time = 240/(x-20) hrs
______________________
Bad time - normal time = 2 hrs
240/(x-20) - 240/x = 2
120/(x-20) - 120/x = 1
120x -120(x-20) = x(x-20)
20 = x^2 -20x
x^2 - 20x - 20 = 0
x = [20 +- sqrt(20^2 - 4*1*-20)]/2
x = [20 +- sqrt(480)]/2
x = [20 +- 4sqrt(30)]/2
x = 10 +- 2sqrt(30)