Answer:
The exam was out of 75.
Step-by-step explanation:
You know that he earned 65% so more than half his answers were correct.
Then, you would guess and check try 49/60, 49/70, and go up by 10s or 5s. You will then realize that 49÷75 equals 65.333. This rounds up to 65.

Let's Solve ~





or


[ it's similar to expression - a² + 2ab + b² that is equal to (a + b)² ]
so, let's use this identity here to factorise :

I hope it was helpful ~
The sum of the first four terms of the sequence is 22.
In this question,
The formula of sum of linear sequence is

The sum of the first ten terms of a linear sequence is 145
⇒ 
⇒ 145 = 5 (2a+9d)
⇒ 
⇒ 29 = 2a + 9d ------- (1)
The sum of the next ten term is 445, so the sum of first twenty terms is
⇒ 145 + 445
⇒ 
⇒ 590 = 10 (2a + 19d)
⇒ 
⇒ 59 = 2a + 19d -------- (2)
Now subtract (2) from (1),
⇒ 30 = 10d
⇒ d = 
⇒ d = 3
Substitute d in (1), we get
⇒ 29 = 2a + 9(3)
⇒ 29 = 2a + 27
⇒ 29 - 27 = 2a
⇒ 2 = 2a
⇒ a = 
⇒ a = 1
Thus, sum of first four terms is
⇒ 
⇒ 
⇒ S₄ = 2(2+9)
⇒ S₄ = 2(11)
⇒ S₄ = 22.
Hence we can conclude that the sum of the first four terms of the sequence is 22.
Learn more about sum of sequence of n terms here
brainly.com/question/20385181
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Answer:
To find the area of composite figures and use area of a circle to find the radius. Estimate the radius of the circle with the given area.
Step-by-step explanation:
I only say how you can founded