Answer:
Roughly 18,000
Step-by-step explanation:
When you need to do rough mental math, you can do something like 720 vs 25 or 30 which is pretty simple to do in your head.
If you are very proficient in mental math, you can do something like 720 * 25, which is harder, but if you know the tricks, you can do this quickly.
720 * 25
Multiply 25 by 7.
175
Add two zeros.
17,500
Multiply 25 by 2
50
Add a zero.
500.
17500 + 500 = 18000
Answer:
Option C, 30
Step-by-step explanation:
<u>Step 1: Identify how many people spent $200</u>
There was only 30 people that spent $200
Answer: Option C, 30
From the given question we come to know of certain number of facts and they are:
At 1:00 PM the water level of the pond was = 13 inches
At 1:30 PM the water level of the pond was = 18 inches
At 2:30 PM the water level of the pond was = 28 inches
From the above given facts we can easily find the amount of water changing every half an hour.
Amount of increase in water from 1:00PM to 1:30 PM = (18 - 13) inches
= 5 inches
Amount of increase in water level from 1:30PM to 2:30PM = (28 -18) inches
= 10 inches
From the above two deductions we can come to the conclusion the the constant rate of change in water level is 5 inches for every half an hour.
Answer
She used 6/15 litres of oil in January
Explanation
We are given that, in January, she used 3/5 of the amount of oil she used in February.
We are also given that, she used 2/3 litres of oil in February.
Therefore, amount of oil used in January is:
3/5 • 2/3 = 6/15
She used 6/15 litres of oil in January
