Answer:
Step-by-step explanation:
We can let "a" stand for the number of goldfish Andrew has. Then the number Todd has is (70-a). We are told the difference is ...
a - (70-a) = 20
2a = 90 . . . . . . . .collect terms, add 70
a = 45
70-a = 25
Andrew has 45 goldfish; Todd has 25.
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<em>Comment on the problem</em>
I call this a "sum and difference" problem. You are given the total of two counts, and also their difference. If you were paying attention to the above solution, you see that <em>the larger of the counts</em> is (70+20)/2, <em>half the sum of the given numbers</em>. This is generically true of all <em>sum and difference</em> problems.
Knowing this, you can work most of these problems in your head.
There are 1000ml in a litre
1000 divided by 10 is 100
100 groups of 10ml in 1 litre
Speed=6 miles per hour
Distance =9.6 miles
Speed =distance /time
Time=distance/speed=9.6/6=1.6 hours
Answer:
12
Step-by-step explanation:
