<h3>Rate of the boat in still water is 70 km/hr and rate of the current is 15 km/hr</h3><h3><u>Solution:</u></h3>
Given that,
A motorboat travels 165 kilometers in 3 hours going upstream and 510 kilometers in 6 hours going downstream
Therefore,
Upstream distance = 165 km
Upstream time = 3 hours
<h3><u>Find upstream speed:</u></h3>

Thus upstream speed is 55 km per hour
Downstream distance = 510 km
Downstream time = 6 hours
<h3><u>Find downstream speed:</u></h3>

Thus downstream speed is 85 km per hour
<em><u>If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then</u></em>
Speed downstream = u + v km/hr
Speed upstream = u - v km/hr
Therefore,
u + v = 85 ----- eqn 1
u - v = 55 ----- eqn 2
Solve both
Add them
u + v + u - v = 85 + 55
2u = 140
u = 70
<em><u>Substitute u = 70 in eqn 1</u></em>
70 + v = 85
v = 85 - 70
v = 15
Thus rate of the boat in still water is 70 km/hr and rate of the current is 15 km/hr
Answer:
The weight of watermelon at the end of the trip is <u>500 kg.</u>
Step-by-step explanation:
Given:
The weight of watermelons is 1000kg.
At the beginning of the trip watermelon is 99% of the weight:
99% of 1000kg


kg
Now, at the end of the trip it is 98% of weight. So, let
kg of water has been evaporated. So, remaining weight of the watermelon is
.
If
kg of water is removed, then the amount of water left is
.
As per question, water now weighs 98% of the total weight. So,
98% of (
) = 


(Bringing like terms on one side)

Therefore, the weight of watermelon at the end of the trip is given as:
Weight =
= 1000 - 500 = 500 kg
Therefore, the watermelon weighs 500 kg at the end of trip.
Answer:
<h2>10 weeks </h2>
Step-by-step explanation:
Step one:
given data
Ryan
number of baseball cards=150
number collected per week= 10
let the number of weeks be x
and the total be y
y=10x+150-----------------1
Sarah
number of baseball cards=200
number collected per week= 5
let the number of weeks be x
and the total be y
y=5x+200------------2
Step two:
Required
the number of weeks where both total will be the same
10x+150=5x+200
10x-5x=200-150
5x=50
divide both sides by 5
x=50/5
x=10 weeks
2/9 × 3 =
= 2×3 / 9 =
= 6/9 =
= 2/3