Me ayudan por favor con estos ejercicios de álgebra con la 15, 16 y 17

Translate the following situation into an inequality statement . lily has $25 to spend on a charm bracelet for her sisters birthday gift the cost of the bracelet is $12 plus $1.50 per charm

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Aprojectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = -16t2 + 704t. after how many seconds does the projectile take to reach its maximum height?