how would you do these two types of questions? :[
please show an equation D: this assignment's due on monday, heh.
"The sum of all digits needed to write numbers 11 and 12 is equal to 5. What is the sumof all digits needed to write down all whole numbers from 0 to 1000000000?"
and...
"Some people and some horses are in a stable. In total, there are 22 heads and 72 legs. How many people and how many horses are there in the stable?"
Update:ohh. I have another question D:
Heh, sorry. This is just really hard >_<
"Albert spent all his money in 5 stores. In each store, he spent 1$ more than half of what he had before he entered that store. How much money did Albert have when he entered the first store?"
T_T Yeah, it's really hard. :[ To answer your questions, Im in 8th o_o; yeah.
Answers & Comments
Verified answer
1) Each decimal place from the units digit to the hundred-millions digit can be taken up by any digit 0 through 9 (one-digit numbers can be represented as 000,000,001, 000,000,002, etc because we are summing up digits, so 0 does not affect the total). With that in mind, we know that since there are 10 digits and 9 different decimal places, each digit gets used 108=100,000,000 times in each decimal place and thus is used 900,000,000 times total. 900,000,000(0+1+2+3+4+5+6+7+8+9)=40,500,000,000. Since 1 billion is included, we must add 1 to the total, giving 40,500,000,001.
2) p=# people
h=# horses
2p+4h=72
p+h=22 h=22-p
2p+4(22-p)=72
2p+88-4p=72
-2p+88=72
-2p=-16
p=8
8+h=22
h=14
8 people and 14 horses
I cant understand your first question but here is the solution for the 2nd question:
facts:
x = people
y = horse
22 = heads
72 = legs
people have 2 legs, horses have 4 legs
therefore;
x + y = 22
x = 22 - y
2x + 4y = 72
2 (22 - y) + 4y = 72
44 - 2y + 4y = 72
-2y + 4y = 72 - 44
2y = 28
y = 14
y is horses, therefore, there are 14 horses in the stable
x + y = 22
x = 22 - y
x = 22 - 14
x = 8
x is people, therefore, there are 8 people in the stable
First Question is Impossible for me...
Second Question...
22 Horses --> 88 legs...
21 Horses + 1 people --> 84+2=86
Comtinue to reduce the horses by 1 and adding the people by 1 till U get 14 Horses & 8 people:
14 Horses + 8 people --> 56+16=72
Question 2.
People = x
Horses = y
x+y= 22 ---> 1st equation
2x + 4y = 72 ----> 2nd equation
1:: x = 22-y
substitute (22-y) for x in the 2nd equation
2(22-y) + 4y = 72
44-2y+4y = 72
2y = 72-44
y = 28:2
y = 14
from here we know that x = 22 - 14 = 8
there are 8 people and 14 horses.
9
that's between the least puzzling question of Mensuration. (a) the realm of rectangle ABCD= 6x X 5x = 30x² (b) the realm of rectangle EFGH= 4x X 3x = 12x² (c) the realm of the shaded area would nicely be discover by using except for the realm of rectangle EFGH from that of rectangle ABCD and so the mandatory area will be = 30x² - 12x² = 18x² (d) enable the realm of the shaded area is meant to be "a" so "a" = 18x² . Now (i) for x=2 , "a" = 18 X 2² = 18 X 4 = seventy 2 ; & (ii) for x=10 , "a" = 18 X 10² = 18 X one hundred = 1800
i think the second question is 18 horses and 6 people
ur second question is interesting...i am thinking 18 horses and no ppl.
uh i dont know
-teen 360
"And Behold, I am, the God of all flesh...is there anything too hard for me"...