₦airaland Forum

Adex097: x=2

Richiez: You have just started one already, post a question or a topic for discussion and be marvelled at the replies you get

Richiez: well for the sake of others who wants to learn, here's the solution.

first of all, we must recall that Time = Distance/Speed .........(1)
lets convert unit of time to hours only
50mins = 50/60 =5/6 hrs
1hr 15mins =75mins = 75/60 = 5/4 hrs

let running speed = x
and walking speed = y

now applying eqn(1) we get
5/6 = 8/x + 2/y ......................(2)
5/6 = (8y + 2x)/xy
5xy = 6(8y + 2x)
5xy = 48y + 12x
x(5y-12) = 48y
x = 48y/(5y-12)................(3)
also;
5/4 = 6/x + 4/y ...............(4)
putting value of x obtained in eqn(3) into eqn(4) we get;
5/4 = 6(5y-12)/48y + 4/y
multiply thru by 'y'
5y =4[6(5y-12)/48 + 4]
5y= 5y/2 -6 +16
5y/2 = 10
y =20/5 = 4
from eqn(3)
x= 48y/(5y-12)
x= 48(4)/[5(4) -12)]
x= 192/8 =24
therefore running speed= x = 24km/hr
and walking speed = y = 4km/hr

biolabee: you know what guys lets slow down and teach him how to fish
johnpaul can u post what u have done so far
we tell u what uve done wrong
that way u learn the principles better

2nioshine: this is highly manipulative like u said....nd not mathematically acceptd..try it wt other values 2 verify...a great job anyway..

doubleDx: Take a range for the value of x (eg from -2 to 5) and create a table of values for x^2 and 2^x, then plot these two graphs on the same plot. And they will intersect at x = 2 and x = 4 also at x = -0.7...something. And that would be the solution to your question!

biolabee: log both sides

log 2^x = log x^2
x log 2 = 2 log x
log x/x = log 2/2

Well I dont know how to continue but for me x = 2

Johnpaul88: @Johnpaul1101,
I'm happy that my name sake is here. Congrats for coming here and improving yourself.

Freiburger: Answer should be 25

Lets assume the the woman is presently 35 and her son is 10 that adds up to be 45 as stated in the question.
5 years ago the woman was 30, since she is now 35 and her son was 5, since he is now 10. so the woman was 6 times older
so, 5years before the son was born the woman should be 25

@ johnpau1101 how you are O.k with that explanation.

ositadima1: 1) in a two-digit number... "x" and "y"
2) the sum of the digits is 8... x+y=8
3) the difference between this number and the number with the digits reversed is 54... [10y+x]-[10x+y]=54
tnx osita, this was where i got confused
Now,
10y+x-10x-y=54
9y-9x=54
y-x=6

x+y=8
-x+y=6
add these two,
2y=14
y=7
x=1

What is this number?... 71

Ghettoguru: Sorry buddy, we initially got the wrong impression. Keep your questions coming, there are a lot of gurus on this thread willing to help!

Richiez: oh i'm very very sorry i got the wrong impression....okay we all are here to help you okay?