Photomath is a good one. So is KhanAcademy, but I don't know if they have an app version of the website.
I guess this is a geometric series:
a6 = a1 * r^5 so
a1 = 0.03125 / 0.5^5
= 1 answer
Only 25 and 28 are functions.
A function must have only one y value per x value. For 26, the y value of 0 and multiple others have two different y values. For 27, all x values less than 0 have multiple y values.
Total number of students in the class = 36
Number of students wearing blue shirts = (1/6) * 36
= 36/6
= 6
Number of students wearing white shirts = (2/3) * 36
= 2 * 12
= 24
Then
Number of students not wearing blue or white shirts in the class = 36 - (6 + 24)
= 36 - 30
= 6
So 6 students in the class are wearing a shirt other than a blue or a white shirt. I hope the procedure is clear enough for you to understand.