For the first blank, the answer should be the total weight of the solution which is derived from adding 5 grams and 20 grams. The answer would be,
T = 5 + 20 = 25 grams
For the second blank, the % solution is derived by dividing the amount of salt initially by the total amount of the resulting solution. This is as shown below.
I just did 20 times 2 to find out the percent and thats all i did and since you know the 5 grams and 20 grams add them together to get 25 and thats it.