Q&A - PSLE Math

[2cor41618]

isetan:

Hi, another question:


Tan, Lim and Wong had some pens to sell. Tan had the least no. of pens. Wong's no. of pens was 30% less than Lim's. After Tan and Lim had each sold 50% of their pens, Lim had 95 more pens than Tan. If the three men had a total of 330 pens left, what is the total no. of pens they had at first?

At first

Wong---70%
Lim---100%

After T and L sold 1/2 of their share,

Lim---50%
Tan---95 less than 50%
Wong---70%

Thus, 50% + 50% + 70% ----330+ 95
170%---425 (Wong + Lim at first)
1%----2.5
Tan---2x ( 50 x 2.5 - 95) = 60

Total at first----60 + 425 = 485

[tutorsg_punggol]

ksoh3000:

tks

U're welcome! Hope it's not too difficult to understand.

[tamunawara]

thanks a lot . that was really useful

[tamunawara]

thanks a lot . that was really useful

[brastilava]

Hi, please help in this question:


Tin A, Tin B and Tin C are required to paint a complete wall. If only Tin A is used, we are short of 7 litres. If only Tin B is used, we are short of 5 litres. If only tin C is used, we are short of 3 litres. How many litres of paint is required to paint a complete wall?

[tianzhu]

brastilava:

Hi, please help in this question:


Tin A, Tin B and Tin C are required to paint a complete wall. If only Tin A is used, we are short of 7 litres. If only Tin B is used, we are short of 5 litres. If only tin C is used, we are short of 3 litres. How many litres of paint is required to paint a complete wall?

Hi

What is the answer given in the WS?

Best wishes

[brastilava]

Hi Tianzhu, the answer given was 7.5 litres.

[2cor41618]

brastilava:

Hi, please help in this question:


Tin A, Tin B and Tin C are required to paint a complete wall. If only Tin A is used, we are short of 7 litres. If only Tin B is used, we are short of 5 litres. If only tin C is used, we are short of 3 litres. How many litres of paint is required to paint a complete wall?

Hi I think can be solved in the following way:

If only Tin A is used, we are short of 7 litres implies that
B + C = 7 litres--- (1)
Thus following similar logic, we will have
A + C = 5 litres--- (2),
A + B = 3 litres ---(3)

Adding (1), (2) and (3), we have

2A + 2B + 2C = 15 litres
A + B + C = 15/2 = 7.5 litres

[brastilava]

Hi 2cor41618,


Could you explain how you derive:
B+C=7 litres
A+C=5 litres
A+B=3 litres ?

Best Wishes

[brastilava]

Hi 2cor41618,


I finally figure out:) Thanks so much!