He messed up step 2 he added instead of multiplying
20
Step-by-step explanation:
Step 1:
Let the number be 50 and to find 40% of 50 is given interms of expression as follows
To express the percentage the following strategy is used
Eg: 40% = 
∴ To express 40% of 50 is

Step 2:
On simplification the above expression we could get

= 20
Answer:
<h2>50</h2>
Step-by-step explanation:
Put h = 7 to the expression 5 · (h + 3):

7 - 2 = 5
5 / 5 = 1
The answer would be 1.