Answer:
5
Step-by-step explanation:
idek how to explain
There would be 12 people at the party!
In general, with n+1 people, the number of handshakes is the sum of the first n consecutive numbers: 1+2+3+ ... + n.
Since this sum is n(n+1)/2, we need to solve the equation n(n+1)/2 = 66.
This is the quadratic equation n2+ n -132 = 0. Solving for n, we obtain 11 as the answer and deduce that there were 12 people at the party.
Since 66 is a relatively small number, you can also solve this problem with a hand calculator. Add 1 + 2 = + 3 = +... etc. until the total is 66. The last number that you entered (11) is n.
Hope this helps!
80% of 25
percent means parts out of 100
'of' means multiply
80% of 25 means
80/100 times 25=40/50 times 25=20/25 times 25=20
answer is 20 problems
Answer:
x < 4
OR
x > - 2.25
= 4 > x > - 2.25
Step-by-step explanation:
5x - 19 < 1
5x < 1 + 19
5x < 20
x < 20/5
x < 4
OR
- 4x + 3 < - 6
- 4x < - 6 - 3
- 4x < - 9
x > 9/- 4
x > - 2.25
Answer: 24 5 + 9 = 15 + 9 = 24
Step-by-step explanation: