Melody

For a family with 3 children what is the probability that they have exactly 1 boy and 2 girls?

There are 2*2*2=8 combinations

and the boy could be 1st, second or 3rd so that is 3 favourable oucomes so it is   3/8

f'' is positive when f is concave up    x<-1  and x>6

f'' is negative when f is concave down   0

f''=0 when f is not concave up or concave down     -1

Non-differentiable  at  x=-1 and x=0

If you find out that any of these are incorrect then please let me know but I think they are all ok. :)

You have your answer.

There are many different right prisms.

eg  rectangular prism, cube, cylinder, triangular prism, etc etc etc.

For  surface are you just have to work out the area of all the sides seperately and then add them all together. 

type    asin(  )

or press   2nd    sin   

There is a toggle button at the bottom left of the calculator.

Mr Tan was travelling from Town L to Town M at a uniform speed.He drove past Mr Samy who was travelling at a uniform speed of 76 km/h in the opposite direction.1.5 hours later,Mr Tan reached Town M while Mr Samy was still 26 km away from Town L.Mr Tan took 4 hours to travel from Town L to Town M.Find the distance between the two towns.

Let X be the point where they pass each other

That is 1.5 hours into Mr Tan's trip, he has another 2.5 hours to travel.

In that in 2.5 hours My Sammy travels  76*2.5 = 190km which which is 26km less than LX.

So    LX=26+190 = 216km

Mr Tran took 1.5 hours to travel this 216km  so he is travelling at  216/1.5 = 144km/hour

(He is one speedy gonzales!)

After thay pass Mr Tran travels another 2.5 hours       144*2.5=360km    So XM=360km

therefore

LM = 216+360 = 576km

Jack invests $500 at a certain annual interest rate, and he invests another $1000 at an annual rate that is one-half percent higher. If he receives a total of $65 interest in 1 year, at what rate is the $500 invested?

Here is a start  :)

I am using I=PRT which is the same for both simple and compound interest if the time unit is just one. i.e. t=1

Solve this and you will get the initial rate as a decimal. Multiply it by 100 to get  the percentage.

\(65 = 500*r+1000(r+0.005)\)

Hint,

Try drawing a triangle with sides   7cm, 2cm and 3cm

Make the base 7 cm long.

Actually draw this on a peice of paper and see if you can do it, or try to work out why you can't do it :)