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!
6.4 months Because 10% of $1,100 is $110
multiply 110 by 6.4 and you get 704
so 6.4 months
Reorder both sides
3y-6x=9
7-4y-3x=9
Multiply both sides
-6x-3y=9
6x+8y=-4
Dived both sides
11y= 5
Y=5/11
Substitute the value of Y
-3x-4(5/11)
Equals —> -14/11
Answer : (5/11 , -14/11)
Answer:
9632
or
9966
Step-by-step explanation:
im not 100% sure
