If the first three Fibonacci nos. are x1=1, x2=1 and x3=2, what is the value of n for which xn + xn+1 = 89 ?

11

Step-by-step explanation:

Looking at Fibonacci numbers ;

We have:

Than X1 =1 ; X2 = 1; X3 = 2

Xn+1 = Xn + Xn-1

X3 = X2 + X1 = 1+1 =2; X4 = X3 + X2 = 2 +1 = 3; X5= X4+X3 = 3+2 = 5; X6 = X5 + X4 = 5 + 3 = 8; X7 = X6 +X5 = 8 +5 = 13; X8 = X7 + X6 = 13 + 8 = 21; X9 = X8 + X7 = 21+ 13 = 34 ; X10 = X9 + X8 = 34 +21 = 55 ; X11 = X10 + X9 = 55 +34 = 89

We see that ; X11 gives 89 so the value of n = 11

450

step-by-step explanation:

you get texts and minutes, so why not

to find the unit price, we must figure out the cost of one item (in this case one dish towel).   to do this, we divide the total price ($7.92) by the number of items bought (for this problem it is 8, because there are eight dish towels in one pack).  

$7.92/8 = $0.99

therefore, the unit price, or the price of one dish towel, is $0.99.

hope this !