An old man, his age plus 16, divided by 5, then subtracted 10, finally multiplied by 10, is exactly 100 years old, how old is the old man?

An old man, his age plus 16, divided by 5, then subtracted 10, finally multiplied by 10, is exactly 100 years old, how old is the old man?

[（x+16）/5-10]*10=100 x=84

/4 = 0.25 = 4 /? / 28 =?% a math problem,

1;16;7;25

An old man said that his age plus 25, then divided by 3, then subtracted 12, and finally multiplied by 5, is exactly 120 years old. Do you know how old the old man is?
What's the formula

120/5+12*3-25=83

Who will?
1、 Given x ^ 2 + X-1 = 0, find the value of x ^ 3-2x + 4
2、 Given a ^ 2-3a + 1 = 0, find the value of a ^ 4 + 1 / A ^ 4

X^3-2X+4
=X（X^2+X-1）-（X^2+X-1）+3
=3
a^4+1/a^4
=a^4+1/a^4+2-2
=(a^2+1/a^2)^2-2
Because a ^ 2-3a + 1 = 0, a is not equal to 0
A ^ 2 + 1 = 3A divided by a
So a + 1 / a = 3
So (a ^ 2 + 1 / A ^ 2) ^ 2-2
=[（a+1/a）^2-2]^2-2
=(3*3-2)^2-2
=47

An old man said, "add 12 to my age, divide by 4, subtract 12, and multiply by 10. It's exactly 100 years old." how old is the old man now?

(100 △ 10 + 12) × 4-12, = 22 × 4-12, = 88-12, = 76 (years old). A: This grandfather is 76 years old now

1. During blasting, if the burning speed of the fuse is 0.8cm/s and the running speed is 5m / s, how many centimeters must the fuse exceed if the worker who ignites the fuse has to run to the safe area beyond 100m?
2. In 1kg salt water, it contains 4% salt. If salt is added to make it become salt water with concentration no less than 20%, how much salt should be added?

1. People need to run t time to the safe area
(0.008+5)*T=100
T is about 20 (because it's junior high school, the topic is not very rigorous... You can directly use 100 / 5 to get 20)
Fuse length s = 20 * 0.8 = 16cm
2. Water weight = 1000 * 96% = 960 G
Salt weight = 1000 * 4% = 40 g
Let's add x grams of salt
In fact, water does not change, so (40 + x) / (1000 + x) = 20%
The solution is x = 200 g

(1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1) divided by 8888 times 8888, how much is it?
To simplify the calculation,

Multiply by 8888 and divide by 8888 approximately equals one
1 + 7 - = 8 there are 8 8 in total, so it is 64

(4 √ 6-4 √ 1 / 2 + 3 √ 8) divided by 2 √ 2 1 + √ 12 √ 18 - √ 2 (√ 1 / 7 + √ 28 - √ 700) multiplied by √ 7
4 √ 6-4 √ 1 / 2 + 3 √ 8) divided by 2 √ 2 1 + √ 12 √ 18 - √ 3 (√ 1 / 7 + √ 28 - √ 700) multiplied by √ 7. Sorry, I didn't pay attention to the format

4√6/2√2-√16*(1/2)/2√2-6√2/2√2
=2√3-2√2/2√2-3
=2√3-1-3
=2√3-4
1+√18/12-√3
=1+√3/2-√3

A question on the first day of junior high school (- 1.5) * (- 1 and one third) * (- 1.25) * (- 1.2) * (- 1 and one seventh) + one and one sixth

(- 1.5) * (- 1 and a third) * (- 1.25) * (- 1.2) * (- 1 and a seventh) + one and a sixth = 2 * (- 1.25) * (- 1.2) * (- 1 and a seventh) + one and a sixth = - 2.5 * (- 1.2) * (- 1 and a seventh) + one and a sixth = 3 * (- 1 and a seventh) + one and a sixth

One seventh of a number is 6 times more than 2.5. Find the number

2.5*2+6=11
11/(1/7)=77