Answer: 6.698
Step-by-step explanation:
Answer:
160:340
Step-by-step explanation:
The hours between 2:00pm and 4:00pm is 2 hours. If originally 350 freshman and 200 sophomores are at the carnival, and 20 freshman leave every hour, we can determine how many freshman left in 2 hours:
and if 35 sophomores arrive every half our, we know that for every two hours there is 4 half hours, therefore:
The amount of freshman at 4:00pm:
and the amount of sophomores:
the ratio is 160:340
Using the dot product:
For any vector x, we have
||x|| = √(x • x)
This means that
||w|| = √(w • w)
… = √((u + z) • (u + z))
… = √((u • u) + (u • z) + (z • u) + (z • z))
… = √(||u||² + 2 (u • z) + ||z||²)
We have
u = ⟨2, 12⟩ ⇒ ||u|| = √(2² + 12²) = 2√37
z = ⟨-7, 5⟩ ⇒ ||z|| = √((-7)² + 5²) = √74
u • z = ⟨2, 12⟩ • ⟨-7, 5⟩ = -14 + 60 = 46
and so
||w|| = √((2√37)² + 2•46 + (√74)²)
… = √(4•37 + 2•46 + 74)
… = √314 ≈ 17.720
Alternatively, without mentioning the dot product,
w = u + z = ⟨2, 12⟩ + ⟨-7, 5⟩ = ⟨-5, 17⟩
and so
||w|| = √((-5)² + 17²) = √314 ≈ 17.720