Toán Lớp 5: 1. How many pieces of rope of 160cm long are needed to enclose a square of area 100 square meters? 2. How many distinct 4-digit even nu

0 bình luận về “Toán Lớp 5: 1. How many pieces of rope of 160cm long are needed to enclose a square of area 100 square meters? 2. How many distinct 4-digit even nu”

1. Answer:

   1)

   Exchange 160cm = 1.6m

   The area of the square is 100m^2

   => The side of the square is 10m because

   10 × 10 = 100

   The number of pieces of wire 160cm long to take to wrap a square with an area of

   100 m^2 is : 10 : 1.6 = 6.25 ( paragraph )

   Change 6.25 = 6 1/4 paragraph

   Answer: 6 1/4 paragraph

   2)

   The units digit has 3 choices (since it’s an even number, the units digit can only be 0, 2 or 4 )

   Tens digit has 4 choices

   Hundreds digit has 3 choices

   The thousands digit has 1 choice

   So it is possible to generate all even 4 digit numbers that are different:

   3 × 4 × 3 × 1 = 36 ( number )

   Answer: 36 numbers

    

   Trả lời
2. Giải đáp:

    

   Lời giải và giải thích chi tiết:

    1.Lenght of the side of a square is:

   100:10=10 (m)

   10 m= 1000 cm

   Perimeter of a square is:

   1000×4=4000 cm

   The number of pieces we need to enclose a square is:

   4000: 160= 25( pieces)

   xIn lỗi bài 2 mình hok thấy

   Trả lời