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Mathematical jiacang
1、

Let the original price be x.

15%X + 34 =X

X - 15%X = 34

( 100% - 15%)X=34

X = 34 ÷ (85/100)-Let me change the component number, which can also be regarded as 85÷ 100.

X=40

Cheap price = original price-selling price

=40 - 34

=6 (yuan)

2、

Suppose the total number of pages in this book is x .+×℉%

The first day of reading: 20% x pages

Read the next day: 5/8x pages ————————— 5/8.

(5/8)x - 20%x = 34

0.625x-0.2x=34

0.425x=34

x=80

Pages read on the first day = 80× 20% = 16 pages.

3. Classmate, you typed the wrong question:

A car from A to B takes a quarter of the whole journey in the first hour and 20% of the whole journey in the second hour. At this time, it is 9 kilometers away from the midpoint. How many kilometers is it between A and B?

Suppose the whole journey is x.

The remaining first hour: 1/4 x

Leave next hour: 20% x

So half of the total distance is: (1/2) x = (1/4) x+20% x+9.

{( 1/2)-( 1/4)-( 1/5)} x = 9

0.05x=9

X =180km

4. Set up a production team with an area of X mu.

Cultivated land on the first day: 25% x

Cultivated land the next day: (x-25% x) × (2/3) —————————————— two-thirds.

(X-25%X)×(2/3)-25%X=30

0.75X×(2/3)-0.25X=30

0.5X-0.25X=30

X=30÷0.25

X= 120 mu

5. Classmate, there is something wrong with your question. Oh, do you think you have the wrong number? I changed it. Do you think it's the original problem?

There are two packages of candy. The quantity of grain in the first package accounts for two-fifths of the quantity in the second package. In the first package, milk sugar accounts for 30%, and in the second package, other sugar accounts for 42%. If these two packs of sweets are combined, what is the percentage of butterscotch?

Suppose the first packet of sugar has m grains and the second packet of sugar has n grains.

m:n = 2:5 & lt; = & gt2n = 5m & lt= & gtn=2.5m

Percentage of milk sugar in total sugar = {30% m+(1-42%) n} ↓ (m+n) ×100%.

=[{ 30% m+58%×2.5m }/(m+2.5m)]× 100%

=[{(0.3+0.58×2.5)m }/{( 1+2.5)m }]× 100%

= {(1.75m)/(3.25m) }×100%-there is an m above and below the semicolon, which is omitted.

≈ 74.6%

6. The tonnage of grain stored in warehouse A is 40% less than that in warehouse B, and the tonnage of grain stored in warehouse B is a few fractions more than that in warehouse A?

Let a be x and b be y.

The sentence "the tonnage of grain stored in warehouse A is 40% less than that in warehouse B" is conversely "the tonnage of grain stored in warehouse B is 40% more than that in warehouse A", and the answer is two fifths.