Extracurricular study in mathematics, 7th grade

Слайд 2

315 Which values of k cause the lines y = 2x

315

Which values of k cause the lines
y = 2x

– 5,
y = x + 2,
and y = kx – 12
to intersect in a single point?
Слайд 3

364 Roma really likes fantasy and reads three or four pages

364

Roma really likes fantasy and reads three or four pages of

a fantasy novel during each break. He never reads during or after classes. He goes to school five days a week, sitting 28 classes weekly. Last week he has read a total of 78 pages during breaks.
Find the number of breaks during which Roma has read four pages.
Слайд 4

419 The “Pups” company has purchased an automobile on sale at

419

The “Pups” company has purchased an automobile on sale at 35%

below its original price, and sold it at 25% below its original price.
Calculate the percentage of acquired profit.
Слайд 5

450 “Tell me, oh famous Pythagoras, how many students attend your

450

“Tell me, oh famous Pythagoras, how many students attend your talks?”
“This

many,” the philosopher responded, “one half studies mathematics, one quarter studies music, one seventh remains silent, and aside from that, there are three women.
Calculate for yourself how many students I have.”
Слайд 6

454 It takes a squirrel 20 minutes to carry a nut

454

It takes a squirrel 20 minutes to carry a nut into

her nest.
The squirrel runs at 3 m/s with the nut, and at 5 m/s without the nut. How far is the nut tree from the nest?
Слайд 7

457 Present the polynomial x4 – 7x2 +1 as a product

457

Present the polynomial x4 – 7x2 +1 as a product of

two polynomials with whole coefficients.