The mean temperature for the first 4 days in January was 1°C. The mean temperature for the first 5 days in January was 3°C.
What was the temperature on the 5th day?

Step-by-step explanation:

mean is average, so if we label the first through fifth days of january a-e we can solve it.

So average of the first four is (a+b+c+d)/4 = 1 and the first five is (a+b+c+d+e)/5 = 2.  Since it's easy, let's get rid of the fraction in both.

(a+b+c+d)/4 = 1 and (a+b+c+d+e)/5 = 2

a+b+c+d = 4 and a+b+c+d+e = 10

Now, we know a+b+c+d is 4, so we can replace that in the second equation

a+b+c+d+e = 10

4 + e = 10

e = 6

ad since e is the fifth day, we know the temperature of it.  Let me know if something here didn't make sense

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.

at least two

step-by-step explanation: