SOLUTION: Q1. If the population of a certain country increases at the rate of one person every 15 seconds, by how many persons does the population increase in 20 minutes? Q2. Aria has $10.

Question 1158659: Q1. If the population of a certain country increases at the rate of one person every 15 seconds, by how many persons does the population increase in 20 minutes?
Q2. Aria has $10. She gets $4.60 change after buying a packet of rice biscuits.
How much do the biscuits cost?
Q3. there are about 1280 rabbits in that paddock.
They’ve been doubling in number each year for the last seven years.
How many rabbits were in the paddock seven years ago?
Q4. Mother Cat is making mittens for her three cold kittens.
It takes two balls of wool to make mittens for one kitten.
How many balls of wool will Mother Cat need to make mittens for three little kittens?
If one ball of wool costs $2, how much money will the three sets of mittens cost to make?
Q5. Mother Bear is making her 5 bear cubs new coats.
The coats have 3 buttons each.
How many buttons does Mother Bear need?
Q6. A large box contains 18 small boxes and each small box contains 25 chocolate bars. How many chocolate bars are in the large box?
Q7. Kim can walk 4 kilometers in one hour. How long does it take Kim to walk 18 kilometers?
Q8. Linda bought 3 notebooks at $1.20 each; a box of pencils at $1.50 and a box of pens at $1.70. How much did Linda spend?
Q9. Mel had $35 and withdraw some more money from his bank account. He bought a pair of trousers at $34.00, two shirts at $16.00 each and 2 pairs of shoes at $24.00 each. After the shopping, he had $32.00 left. How much money did Mel withdraw from the bank?
Q10. A painter charges $ 225 for materials and $ 35 per hour for labour. The total cost of painting an office is $ 330. How many hours did it take the painter to paint the office?

Found 2 solutions by ikleyn, jim_thompson5910:
Answer by ikleyn(52858) (Show Source): You can put this solution on YOUR website!
.

There is a RULE, a POLICY and a REQUIREMENT in this forum:

One and ONLY ONE problem/question per post.

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

I'll do the first problem to get you started.

The population increases at a rate of 1 new person every 15 seconds
We can write the ratio
1 person: 15 seconds

Multiply both sides by 4 so that "15 seconds" turns into "60 seconds"
Then we can replace "60 seconds" with "1 minute"

1 person: 15 seconds
4*1 person: 4*15 seconds
4 people: 60 seconds
4 people: 1 minute

The population is increasing by 4 people per minute.

Lastly, multiply both sides by 20 so that "1 minute" turns into "20 minutes"

4 people: 1 minute
20*4 people: 20*1 minute
80 people: 20 minutes

After 20 minutes, there are 80 new people.

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