Q&A - P4 Math

[MathIzzzFun]

kaimono:

Pls help to solve this problem using units. thanks

There were twice as many blue clips as yellow clips in the box.
After giving away 66 blue chips and 8 yellow clips, there were thrice as many yellow clips as blue clips left in the box.
How many clips were there in the box at first?

Hi

you can use MD, or units method.

In the end,
Blue chips --> 2 units
Yellow chips --> 6 units ... since thrice as many yellow as blue chips.

At first,
Blue chips --> 2 units + 66
Yellow chips --> 1 unit + 33 .. since twice as many blue as yellow

Comparing yellow chips, before and after:
1 unit + 33 - 8 = 6 units
5 units --> 25, 1 unit --> 5

At first,
blue chips --> 2 x 5 + 66 = 76
yellow chips --> 5 + 33 = 38
total --> 114 blue & yellow chips

cheers.

[kaimono]

Thanks MathIzzzFun

[MathIzzzFun]

kaimono:

Thanks MathIzzzFun

u r welcome

cheers.

[Cheerfuldad]

snowball:

1st step :

find the different ( 4 legs - 2 legs) = 2 legs

2nd step :
assume all 41 heads belongs to the animal that has the lesser no. of legs ie.chickens

thus, 41 heads x 2 legs = 82 legs

3rd step:
118 legs - 82 legs = 18 ( this is the no. of horse )

final step:
41-18=23 ( this is the no. of chickens )

Hi snowball,

Thank you for your answer!

Regards

[Cheerfuldad]

Mychildren:

Hi, snowball, the third step 118-82 = 36 why is it 18?


Hi, cheerfuldad, I used guess and check:
Chicken21x2=42 Horse20x4 =80 Total heads 41 but legs 122 so not correct.
Chicken22x2=44 Horse19x4=76 Total heads 41 but legs 120 so not correct.
Chicken23x2=46 Horse18x4=72 Total heads 41 and legs 118 so this is the answer.

Hi Mychildren,

Thank you!

I used guess and check method as well but snowball's method is more time efficient i think.

Regards

[Mychildren]

Its all right. Its all depends on which method you and your child is comfortable with.

[chloecube]

Andy n Ben have $680 altogether. After Andy spent 1/3 of his money n Ben spent 1/4 of his money, they will have equal amount of money left. How much did Ben have at first?

[MathIzzzFun]

chloecube:

Andy n Ben have $680 altogether. After Andy spent 1/3 of his money n Ben spent 1/4 of his money, they will have equal amount of money left. How much did Ben have at first?

Hi

Andy and Ben had equal amount left. So,
2/3 Andy's money = 3/4 Ben's money
6/9 Andy's money = 6/8 Ben's money
Andy's money --> 9 units
Ben's money --> 8 units
Ben's money at first = 8/17 x $680 = $ 320

cheers.

[chloecube]

thks mathIzzzFun,


so for this type of question is to change the nemerator to the same instead of denominator.

thks

[MathIzzzFun]

chloecube:

thks mathIzzzFun,


so for this type of question is to change the nemerator to the same instead of denominator.

thks

Hi

it is \"shortcut\" to determine the ratio.. the rationale can be understood easily when we draw the model as shown below:

http://i49.tinypic.com/2vljic9.png\">

cheers.