Others Maths Puzzle

A motorboat went downstream for 28km and immediately returned. It took the boat twice as long to make the return trip. If the speed of the river flow were twice as high, the trip downstream and back would take 672 mins. Find the speed of the the boat in still water and the speed of the river flow.

a. 9km/h, 3km/h
b. 9km/h, 6km/h
c. 8km/h, 2km/h
d. 12km/h, 3km/h.

Read Solution (Total 1)

Others Other Question


Importance High!!!!!!!!!!!!!!!!!

Dear Sir / Madam

Myself Rajeev Shrivastava, I am putting a signs series in front of you which based on numbers from 01 to 100. Actually I want to know that what reason of behind Approx equability of signs is
(++), (+-), (--) & (-+) at end of the month or year between the below mentioned.

Let's define a kind of mapping:
0↔1
2↔3
4↔5
6↔7
8↔9

(+) means: an Even number
(-) means: an Odd number

I simply say: for any EO (+-) it exists an OE (-+) which is paired to.
And that's true since each E is mapped to a O and vice versa (1 to 1 relation where "f(f(x))=x" ) !
E.g.: 29 ↔ 83

There is 25 numbers in the EO (+-) group, so 25 in OE (+-).
There is 25 numbers in the EE (++) group, so 25 in OO (--).

Picking a number at random between 01 and 100 inclusive is choosing equitably in EO, OE, EE or OO group. (25% for each)

So, I really need of your help to solve a puzzle please. I just am trying to make you understand what type of solution I need:

There are some results for your review:
MONTH
DATE DAY FIRST_SERIES SECOND_SERIES FIRST_SERIES SECOND_SERIES
APR 1 SUN + - - + +- -+
APR 2 MON + + - + ++ -+
APR 3 TUE + - + - +- +-
APR 4 WED + + + + ++ ++
APR 5 THU - + - + -+ -+
APR 6 FRI + + + - ++ +-
APR 7 SAT + - - + +- -+
APR 8 SUN - + + - -+ +-
APR 9 MON - + - + -+ -+
APR 10 TUE + + + + ++ ++
APR 11 WED + + - - ++ --
APR 12 THU - + - - -+ --
APR 13 FRI + + + + ++ ++
APR 14 SAT + - + - +- +-
APR 15 SUN + - + - +- +-
APR 16 MON - - + + -- ++
APR 17 TUE - - + + -- ++
APR 18 WED
APR 19 THU
APR 20 FRI
APR 21 SAT
APR 22
APR 23

(Complete sheets for the year 2011 and 2012 are attached with this mail)

You can see that there are two times falls in a day of pair make by even (+) and odd (-) signs, i.e. (++), (+-), (--) & (-+) as above said.
The total of pair combination signs become approx equal to each other at the end of the month or year (every year- so, I am sending you attachment to go through the year’s result).
By this analysis:
1- I want to know that what is the relation between current falling signs and past fell signs.
2- How can I come to know, what type of combination of sign would be any particular date or day.
3- As you can seen on 22nd and 23rd April’2012 I don’t know what combination of sign is.
4- There is surety that there is some relation between current First fall of combination of signs and past fall or First fall of combination of signs and Second fall of combination of signs.

Please help me to how come to know what type of fall may be for next day by reviewing past or first combination of signs. So reply or elaborate me with an example.

I would be very grateful to you till entire life.

Regards

RAJEEV SHRIVASTAVA
 How many natural numbers b/w 1 and 900 are not multiples of any of the numbers 2,3,5 ?

1.240
2.250
3.270
4.300