I went to the doc to get some med before my sore throat worsens. Seemed like my sore throat only got worse after I start teaching for 3 hours non-stop. My mood got worse also and I started to raise my voice and got irritated.
Anyway, maths question for everybody to solve
There are 3 taps which can fill the tank in 20 min. Tap A fills the tank in 45 min. Tap B fills the tank in 60 min. How long does Tap C take to fill the tank?
I gave this qns to an O level student to solve. And he doesn’t know how to. Of course I stressed him by telling him that it is a pri 5 math qns which is true.
So what is the ans?
Wah, Primary 5 nowadays have such hard questions?
Anyway, here’s my working:
A,B & C fill the tank in 20 mins, which means the 3 taps can fill 3 tanks in 1 hour.
A fill 1 tank in 45 mins, which means A can fill 1 1/3 tank in 1 hour.
B fill 1 tank in 1 hour.
Hence, in 1 hour, C can fill [3 - (1 1/3 + 1)] = 2/3 of the tank.
Which means C will take [1/(2/3)] = 1 1/2 hrs = 90 mins to fill up the tank.
Correct?
yep.. that’s correct.. wow primary 5 does these kinda questions? lol.. got me stumped for a minute.. ^_^
yup correct. Bravo KM. hahaha. I did the qns the same way just that i did it in terms of one minute instead of one hour.