Questions

The biggest concern is the cost incurred for test automation. Also, often s/w test automation requires skilled personnel and authentic test automation tools. Purchasing license of such tools is a costly affair.

Also the time required for test automation is more. Automation often requires recording the sequence of operations you need to perform in order to execute a particular test case and comparing the final o/p with the expected o/p. Functions/macros need also be written sometimes for some test cases. All this could be a time consuming job. 

Sum of all numbers in each row and columns must be 15.

In last row to gt sum as 15 missing number must replaced by 1. 

We know that polar substances are soluble in polar solvents and non polar substances are soluble in non-polar solvents only. Here the hydrocarbons are non-polar molecular substances and water is a polar solvent. So water can't dissolve hydrocabons.

Hence, as hydrocarbons are non-polar substances, they are insoluble in water as it is a highly polar solvent.