2 blocs cote a cote

<div id="centre">
  	<div>
	        <p class="bloc_droite">bloc de droite<br />blog de droite</p>
        	<p class="bloc_gauche">bloc de gauche<br />blog de gauche</p>
	</div>
	<div>
		<p class="bloc_droite">bloc de droite<br />blog de droite</p>
		<p class="pub_carre"><img src="/image_carre.jpg"></p>
	</div>
	<div>
		<p class="bloc_droite">bloc de droite<br />blog de gauche</p>
        	<p class="partenaire"><img src="/pub_partenaire.jpg"></p>
	</div>
</div>

#centre {
	background-color: #E6EDFC;
	width: 670px;
}
.bloc_gauche{
        margin: 10px 0px 0px 175px;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 275px;
}
.bloc_droite{
	margin: 10px 0px 0px 500px;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 275px;
}
.pub_carre{
        margin: 10px 10px 10px 175px;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 300px;
	height: 250px;
}
.partenaire{
        margin: 10px 10px 10px 175px;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 234px;
	height: 60px;
}

 

.bloc_gauche{
	float: left;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 275px;
}
.bloc_droite{
	float: right;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 275px;
}
.pub_carre{
    float: left;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 300px;
	height: 250px;
}
.partenaire{
    float: left;
	background-color: #4F87FD;
	border: 2px solid #000000;
	width: 300px;
	height: 60px;
}