Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**cat1kf2****Member**- Registered: 2012-11-15
- Posts: 3

After 3 days, there are 1,600 bacteria. How many bacteria were there at the beginning of the first day? Use the work backward strategy.

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,271

hi cat1kf2

Welcome to the forum.

Work backwards:

After 3 days ....................1600

12 hours earlier................ 1600 ÷ 2

after two days .................. ÷ 2 again

12 hours earlier ................ ÷ 2 again

After one day ................... ÷ 2 again

12 hours ealier ................. ÷ 2 again

start ................................ ÷ 2 again

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**SMBoy****Banned**- Registered: 2012-11-17
- Posts: 13

Is The Answer above correct? as there is no reply?

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,271

hi SMboy,

Welcome to the forum.

What answer are you talking about ?

I gave a method, but deliberately did not say what I thought the answer is.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**Ms_Zee****Guest**

Hi SMboy,

The explanation you received from bob bundy is correct, you just need to work out the result.

[removed by administrator]

Hi;

The use of this site for personal advertising is forbidden. Everyone here is a volunteer. We have teachers, mathematicians, physicists, engineers, students and me all answering questions for nothing. If you would like to add your expertise to our group then that would be fine.

**mathgogocart****Member**- Registered: 2012-04-29
- Posts: 1,448

according to bob bundy(thank you)

the Awser is 25

Hey.

Offline

**SMBoy****Banned**- Registered: 2012-11-17
- Posts: 13

Thank's all I understand now how it works.

Offline

**cat1kf2****Member**- Registered: 2012-11-15
- Posts: 3

bob bundy wrote:

hi cat1kf2

Welcome to the forum.

Work backwards:

After 3 days ....................1600

12 hours earlier................ 1600 ÷ 2

after two days .................. ÷ 2 again

12 hours earlier ................ ÷ 2 again

After one day ................... ÷ 2 again

12 hours ealier ................. ÷ 2 again

start ................................ ÷ 2 again

Bob

Thanks for your help Bob

Offline

**cat1kf2****Member**- Registered: 2012-11-15
- Posts: 3

mathgogocart wrote:

according to bob bundy(thank you)

the Awser is 25

thanks for your help

Offline