The answer is 244 because you add 35 to 287 then subtract 78 and it equals 244
Answer:
It will take 58 seconds
Step-by-step explanation:
If you have 1 kg of water in the jar, half of it will be 0.5 kg.
To vaporize half of the water (0.500 kg) the energy supply needed is

If the stove is supplying 20 kJ/s, the time its needed is

It will last at least 58 seconds to vaporize half of the water.
Adding/subtracting fractions requires that they have the same common denominator. In this case they already have 8 in both denominators. Once they have a common denominator addition/subtraction can be carried out as follows:
rule: a/c+b/c=(a+b)/c... in this case
3/8+2/8
(3+2)/8
5/8
Answer:subtract
Step-by-step explanation:
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