PSLE A rectangular block U was cut along the dotted line into two smaller rectangular blocks of equal height, V and W, as shown. The volume of W is 7220 cm
3 more than that of V.
- What is the height of each block?
- Reggie packed 6 of block W such that they fit exactly into a box with a square base. The box has the same height as W. At most, how many of block V can be packed into such a box?
(a)
Base area of Block V
= 11 x 20
= 220 cm
2 Base area of Block W
= 30 x 20
= 600 cm
2 Base area of Block W more than Block V
= 600 - 220
= 380 cm
2 Height of each block
= 7220 ÷ 380
= 19 cm
(b)
Base area of the box
= 6 x 600
= 3600 cm
3 Length of the box
= √3600
= 60 cm
Number of Block V along the length of the box
= 60 ÷ 11
= 5 r 5
Number of Block V along the breadth of the box
= 60 ÷ 20
= 3
Number of Block V to pack into the box at most
= 5 x 3
= 15
Answer(s): (a) 19 cm; (b) 15