Cross multiplication
or multiplying by a number which goes in both rates
Money of account is 58.19+2.74__60.85
90/2 = 45
45/1700 = 0.02647
0.02647 x 100 = 2.64
2.46%
To get 4 or fewer correct, at least 2 answers have to be wrong. And the probability of that is:
3/4 x 3/4=9/16
1-9/16=probability that 4 or fewer are correct=7/16 ☺☺☺☺
