Q&A - P5 Math

[BigDevil]

Tap Y can fill an empty tank in 6 minutes. When Tap Y and Tap Z are turned on at the same time, they can fill the empty tank in 4 minutes. How long does it take for Tap Z to fill the empty tank?

Is the answer 12 minutes?

[speedmaths.com]

Tap Y can fill an empty tank in 6 minutes. When Tap Y and Tap Z are turned on at the same time, they can fill the empty tank in 4 minutes. How long does it take for Tap Z to fill the empty tank?

Is the answer 12 minutes?

Hi,

Yes, 12 mins.


speedmaths

[BigDevil]

[ttlkbs]

96/2 - 20 = ans

triangles with common base or height

Maths, make it easy!

Can you explain the logic behind? Thanks a million!

note that area of triangle CFG = area of triangle CFE.

and area of triangle CFE + area of triangle ADF = half of area of rectangle ABCD.

So 96/2 - 20 = 28.

I am very sorry that I still don't understand!

[Laurel111]

Tap Y can fill an empty tank in 6 minutes. When Tap Y and Tap Z are turned on at the same time, they can fill the empty tank in 4 minutes. How long does it take for Tap Z to fill the empty tank?

Is the answer 12 minutes?

Hi,

Yes, 12 mins.


speedmaths

Can you please explain how to get 12min? thanks.

[Nebbermind]

Tap Y can fill an empty tank in 6 minutes. When Tap Y and Tap Z are turned on at the same time, they can fill the empty tank in 4 minutes. How long does it take for Tap Z to fill the empty tank?

Is the answer 12 minutes?

Hi,

Yes, 12 mins.


speedmaths

Can you please explain how to get 12min? thanks.

Y fills 1/6 of the tank in 1 min
Y+Z fill 1/4 of the tank in 1 min
Therefore Z fills (1/4-1/6) = 1/12 of the tank in 1 min
Z needs 12 mins to fill whole tank.

[Laurel111]

Thank you Nebbermind.

[belnanna]

Stuck... Help please.. Thanks in advance

A store sells pens in packs of 2s (small) and 4s (big).
At first there were 3 times more small packs than big packs.
After selling half of the small packs and some big packs, the shopkeeper packs
additional 5 big packs of pens. How many big packs are sold if there are thrice as many small packs as big packs and there is total 300 unsold pens?

[belnanna]

96/2 - 20 = ans

triangles with common base or height

Maths, make it easy!

Can you explain the logic behind? Thanks a million!

note that area of triangle CFG = area of triangle CFE.

and area of triangle CFE + area of triangle ADF = half of area of rectangle ABCD.

So 96/2 - 20 = 28.

note that area of triangle CFG = area of triangle CFE.
Can explain in details please, also dont understand ... Thanks

[ttlkbs]

The triangle CFG and CFE have the same base CF, and the same height (as point G and point E are on the rectangle, so perpendicular height is the same. Well not necessary rectangle, as long as the points lies on the line parallel to the base).

As formula of area of triangle is 1/2 x base x height, so area of triangle CFG = area of triangle CFE.

In fact, this is a property to be remembered when study area of rectangle and triangle.

and area of triangle CFE + area of triangle ADF = half of area of rectangle ABCD.

So 96/2 - 20 = 28.