86. ask what is the unit digit of n?
a. n is divided by 5, reminant is 3
b. n divided by 4, no reminant

87.some money deposit to bank, ask for the simple interest rate
a. each $70 , get $2.10 interest.
b. each $20 , get $0.66 interest

88.$20.000 deposit into bank, compand quarterly, ask for this compand interest.
a.the intrest in 2nd quarter is 1.1 times more than the first quarter.
b. the intrest in 2nd quarter is 2 dollars more than the first quarter.

89. s=0.abc. ask s is more than 2/3?(old jj)
a.a+b is more than 14
b. a+c is more than 15

90. six musicians put into order, 3 of them have to be put together(their order does not matter), ask how many ways?

91.a1=3, a2=5, a(n+1)=an-a(n-1), ask s100=?(old jj)

92.buy wines, first 5 bottle $8each bottle, from 6 to 10(inclusive) $7each, more than 10 is $12 each. buy seperate $32 and $61, ask if buy together how much need to pay.(old jj)

93. 1/(9- 4xsqurt5) old jj