Answer:
x<84
Step-by-step explanation:
First, write an inequality. We know it is not an equation because of the words "less than". Also, x and 8 are being added because of the word "and". Here's the inequality: x+8 < 72. Now, subtract 8 on both sides so x is isolated. Our simplified inequality looks like this: x < 84.
Suppose
At the same time, we can write
Note that 
(just reverse the sum). Let's pair the first terms of 
and 
, and the second, and the third, and so on:
Now, each grouped term in the sum on the right side adds to 151. There are 52 grouped terms on that same side (because there are 50 numbers in the range of integers 51-100, plus 50 and 101), which menas
But , as we pointed out, so
X = 3
y = -3
You will see this using any graphing tool at your disposal.
Answer: 5 km walking and 30 km by bus
Step-by-step explanation:
Yochanan walked from home to the bus stop at an average speed of 5 km / h. He immediately got on his school bus and traveled at an average speed of 60 km / h until he got to school. The total distance from his home to school is 35 km, and the entire trip took 1.5 hours. How many km did Yochanan cover by walking and how many did he cover by travelling on the bus?
walking - 5km/h bus - 60km/h
distance walking - d₁ distance bus - d₂
time walking - t₁ time bus - t₂
d₁ + d₂ = 35
t₁ + t₂ = 1.5
v = d/t
vwalking = d₁/t₁
5 = d₁/t₁ ⇒ d₁ = 5t₁
vbus = d₂/t₂
60 = d₂/t₂ ⇒ d₂ = 60t₂
d₁ + d₂ = 35 ⇒ 5t₁ + 60t₂ = 35
_________________________
5t₁ + 60t₂ = 35
t₁ + t₂ = 1.5 (*-5)
5t₁ + 60t₂ = 35
-5t₁ -5t₂ = -7.5 (+)
__________________________
55t₂ = 27.5
t₂ = 27.5/55 = 0.5 h
t₁ + t₂ = 1.5 ⇒ t₁ = 1.5 - 0.5 = 1h
d₁ = 5t₁ ⇒ d₁ = 5.1 = 5 km
d₂ = 60t₂ ⇒ d₂ = 30.0.5 = 30 km
