1. How many bricks each measuring 25cm×11.25cm×6cm, will be needed to build a wall of 8m×6m×22.5? 2. what decimal of an hour is a second? 3. without a calculator, 0.04×0.0162 is equal to...... 3. (0.04)^ -1.5 4. if m and n are whole numbers such that m^n=121, the value of (m-1)^n+1 is

#1

800*600*2250
----------------- = 640,000
25*11.25*6

1s = 1/3600 hr = 0.0002777777...

4*162 = 648, so
.04*.0162 = 648/(100*10000) = .000648

.2 = .04^0.5, so
.2^3 = .008 = .04^1.5
1/.008 = 125 = .04^-1.5

11^2 = 121, so 10^3 = 1000

1. To find the number of bricks needed to build a wall, we need to calculate the volume of the wall and the volume of each brick. Then, we divide the volume of the wall by the volume of each brick to get the number of bricks required.

The volume of the wall can be calculated by multiplying its length, width, and height:
Volume of wall = Length × Width × Height = 8m × 6m × 22.5m = 1080 cubic meters

The volume of each brick can be calculated similarly:
Volume of brick = Length × Width × Height = 0.25m × 0.1125m × 0.06m = 0.0016875 cubic meters

Now, we divide the volume of the wall by the volume of each brick:
Number of bricks needed = Volume of wall / Volume of brick = 1080 cubic meters / 0.0016875 cubic meters ≈ 639,851 bricks

Therefore, approximately 639,851 bricks measuring 25cm×11.25cm×6cm will be needed to build the wall.

2. To find out what decimal of an hour a second is, we need to convert both the time units to a common format.

There are 60 seconds in a minute, and there are 60 minutes in an hour. So, there are a total of 60 * 60 = 3600 seconds in an hour.

To find the decimal of an hour that a second represents, we divide 1 second by the total number of seconds in an hour:
Decimal of an hour = 1 second / 3600 seconds = 0.000277778

Therefore, a second represents approximately 0.000277778 decimal of an hour.

3. To multiply 0.04 and 0.0162 without using a calculator, you can use the method of multiplication with decimals:

Step 1: Ignore the decimal points and treat the numbers as whole numbers.
0.04 × 0.0162 = 4 × 162

Step 2: Multiply the whole numbers.
4 × 162 = 648

Step 3: Count the total number of decimal places in the original numbers.
In this case, there are three decimal places (two in 0.04 and one in 0.0162).

Step 4: Place the decimal point in the answer by counting three places from the right:
648 becomes 0.648

Therefore, 0.04 × 0.0162 is equal to 0.648.

4. To find the value of (m-1)^(n+1), we need to use the information given that m^n = 121.

Given that m^n = 121, we know that m × m × m × ... (n times) = 121.

Since 121 is a perfect square, we can see that m must be the square root of 121, which is 11. So, m = 11.

Now let's substitute this value of m in the expression (m-1)^(n+1):

(m-1)^(n+1) = (11-1)^(n+1) = 10^(n+1)

Since 10 raised to any power gives a value with a trailing zero, we know that the expression will end with a zero.

Therefore, the value of (m-1)^(n+1) is a number that ends with zero, and the specific value depends on the value of n.