The three possible ways and their probabilities are in ry1.
The total probability is 2/125 + 4/125 + 4/125 .
IV is wrong, either they should be converted to improper fractions or be explicitely written as sum of whole numbers and fractions.
Let the original number of bacteria be 100 . After an hour there will be 90 and after two 99 .
1/3 x 1/5 x 2/7 is being asked.
II is relatively harder to reduce. For the others, after reductions 5/12 , 4/21 and 16/69 are obtained .
Let the original speeds be 100 km/hour. After the first stage these will reduce to 70 and then ... .
The population, depending on years, will be : 1+3/200, (1+3/200)x(1+3/200), (1+3/200)x(1+3/200)x(1+3/200), ... . The population increase and land decrease
are calculated approximately in ry1 and 2 .
For the population increase we found per capita 1+3/10 and land decrease per unit area we found 1-2/25. Per capita land will be (23/25):(13/10)= 46/65 which
is of course to be multiplied by 7/2 acres of today. 7/2 x 46/65 = 7 x 23/65 = 161/65 = 2 31/65 .
AxB is supposed to be ≤5 . If B=1, there are 5 possibilities, all others are also covered.
(5x7x24)/(6x12x11) = ?
It may be written in the form 10/3 x 1/30 = A x 1/30 .
(A-1) x (B-3) should be ≤ 35; negative fractions are permitted .
Choice d has a dominant factor like 1/100 .
5/3 x 21/5 = ?
In case A=65 it is equivalent to unity.
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