In the first series, the summation applies to the whole (2n+3) inside
the parentheses, so the 3 gets summed up 5 times.
But in the second one, the summation only applies to the 2n , so
the 3 is only added after the summation is finished.
The difference between five 3s the first time and one 3 the second time
is your 12 .
To solve this, you can set up an equation. Make the length of the shortest side x, so the 2 sides double the length will equal 2x. Since they all equal the perimeter of 36, do x + 2x + 2x =36. These values all represent the sides(2 longer, one short). Combine like terms to get 5x=36 then divide by 5 to find the value of x. x=7.2in meaning the shorter side is 7.2 inches while the longer sides are both 14.4 inches each since they are double in size.
Probability of rolling a sum of 9 or a sum that is even from two number cubes is
11/18
Explanation:
When a dice is rolled there are different ways in which
9. can be obtained, which are (3,6) or (4,5) or (5,4) or (6,3). 4 options. As in all there are
6⋅6=36 options, probability is 4/36 or 1/9.
For getting an even number as sum, we can have (1,1) or (1.3) or (1,5) or (2,2) or (2,4) or (2,6) or (3,1) or (3,3) or (3,5) or (4,2) or (4,4) or (4,6) or (5,1) or (5,3) or (5,5) or (6,2) or (6,4) or (6,6) 18 options, probability is 18/36 or 1/2.
Note that the two events (getting 9 or even sum) are mutually exclusive, the probabilities can be just added i.e. combined probability is
1/9+1/2=2+9/18i.e. 11/18
Area of a square quilt = 289 square inches
Area of a smaller square quilt = 121 square inches
Area of a square = a²
Side length of big square quilt = √289 in² = 17 inches
side length of small square quilt = √121 in² = 11 inches
Perimeter of big square = 17 inches * 4 = 68 inches
perimeter of small square = 11 inches * 4 = 44 inches
difference = 68 inches - 44 inches = 24 inches.
