Anew computer can complete a complex biochemistry calculation in 7 hours less than an older-model computer. working together, the new computer and the old computer can complete the calculation in 13 hours. how long would it take the new computer to complete the calculation by itself? round to the nearest tenth of an hour.

The rate a computer works is 1/time. Working together, you add the rates.
Let new computer be x, old computer be y.
x = y - 7


Rounded to nearest tenth gives:
x = 23 hours

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.